You searched for subject:( catenary action). Showing records 1 – 14 of 14 total matches.
1. Beshir, Moustafa Abdelghaffar Elgharib zayed. ROBUSTNESS OF COMPOSITE FRAMED STRUCTURES IN FIRE.
Degree: 2016, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:298477
► This thesis presents the results of a research study to investigate the behaviour of axially restrained composite beams at ambient and elevated temperatures, and how… (more)
▼ This thesis presents the results of a research study to investigate the behaviour of axially restrained composite beams at ambient and elevated temperatures, and how composite beams and their connections contribute to the robustness of composite framed structures in fire. The commercial finite element analysis package (ABAQUS, 2010) was used to develop the numerical simulation models. This research includes the following four main parts: (1) validation of the simulation model; (2) behaviour of axially restrained composite beams with partial shear interaction at ambient and elevated temperatures; (3) behaviour of composite beams with realistic connections at elevated temperatures and methods of increasing composite beam survival temperatures; and (4) response and robustness of composite frame structures with different extents of damage at elevated temperatures.Based on the results of composite beams, it was found that the survival of axially restrained beams is dominated by the development of catenary action. By utilising catenary action, it is possible for composite beams to develop load carrying capacity significantly above that based on bending resistance. During the development of catenary action, the compression force in the concrete flange of the composite beam decreases, thus reducing the forces in the shear connectors. As a result, the behaviour of shear connector failures ceases to be an issue during the catenary action stage. The results further show that, the load carrying capacities/survival temperatures of composite beams increase by increasing the level of axial restraint up to a certain limit and then decrease at higher levels. Typical realistic composite structures can provide composite beams with sufficient axial restraint to develop catenary action. For detailed composite beams with composite connections, three different beam sizes were investigated using flushed and extended end plate connections with different amounts of slab reinforcement, different load ratios and different bolt sizes. It has been found that the most important method to increase the survival time of composite beams is to use extended end plate connections with sufficient top and bottom reinforcement meshes in the concrete slab, i.e. increasing the amount of slab reinforcement is more beneficial than increasing the bolt size or the number of bolts.Based on the results of modelling a four bay (9 m each, two storey, 4 m high) composite frame with different extents of fire damage to different members, it was found that whenever any of the columns failed, progressive collapse of the frame would occur. Therefore, damages to columns should be prevented or the columns should be designed and constructed to allow for possible damage. If the beams are damaged, it is still possible for the damaged frame to achieve the reference fire resistance time of the undamaged structure (which is used as the criterion to accept that the damaged frame has sufficient robustness) by developing catenary action in the damaged beam. For this to happen, the… Advisors/Committee Members: SWAILES, TOM T, Swailes, Tom, Wang, Yong.
Subjects/Keywords: Robustness; Composite steel concrete structure; catenary action; Fire; Partial damage
Beshir, M. A. E. (2016). ROBUSTNESS OF COMPOSITE FRAMED STRUCTURES IN FIRE . (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:298477
Beshir, Moustafa Abdelghaffar Elgharib. "ROBUSTNESS OF COMPOSITE FRAMED STRUCTURES IN FIRE." 2016. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:298477.
Beshir, Moustafa Abdelghaffar Elgharib. "ROBUSTNESS OF COMPOSITE FRAMED STRUCTURES IN FIRE." 2016. Web. 22 Jan 2020.
Beshir MAE. ROBUSTNESS OF COMPOSITE FRAMED STRUCTURES IN FIRE. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2020 Jan 22]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:298477.
Beshir MAE. ROBUSTNESS OF COMPOSITE FRAMED STRUCTURES IN FIRE. [Doctoral Dissertation]. University of Manchester; 2016. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:298477
2. Beshir, Moustafa. Robustness of composite framed structures in fire.
Degree: PhD, 2016, University of Manchester
URL: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-composite-framed-structures-in-fire(9c72a722-5b6a-477b-ac84-cd243ab73f34).html  ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713557
▼ This thesis presents the results of a research study to investigate the behaviour of axially restrained composite beams at ambient and elevated temperatures, and how composite beams and their connections contribute to the robustness of composite framed structures in fire. The commercial finite element analysis package (ABAQUS, 2010) was used to develop the numerical simulation models. This research includes the following four main parts: (1) validation of the simulation model; (2) behaviour of axially restrained composite beams with partial shear interaction at ambient and elevated temperatures; (3) behaviour of composite beams with realistic connections at elevated temperatures and methods of increasing composite beam survival temperatures; and (4) response and robustness of composite frame structures with different extents of damage at elevated temperatures. Based on the results of composite beams, it was found that the survival of axially restrained beams is dominated by the development of catenary action. By utilising catenary action, it is possible for composite beams to develop load carrying capacity significantly above that based on bending resistance. During the development of catenary action, the compression force in the concrete flange of the composite beam decreases, thus reducing the forces in the shear connectors. As a result, the behaviour of shear connector failures ceases to be an issue during the catenary action stage. The results further show that, the load carrying capacities/survival temperatures of composite beams increase by increasing the level of axial restraint up to a certain limit and then decrease at higher levels. Typical realistic composite structures can provide composite beams with sufficient axial restraint to develop catenary action. For detailed composite beams with composite connections, three different beam sizes were investigated using flushed and extended end plate connections with different amounts of slab reinforcement, different load ratios and different bolt sizes. It has been found that the most important method to increase the survival time of composite beams is to use extended end plate connections with sufficient top and bottom reinforcement meshes in the concrete slab, i.e. increasing the amount of slab reinforcement is more beneficial than increasing the bolt size or the number of bolts. Based on the results of modelling a four bay (9 m each, two storey, 4 m high) composite frame with different extents of fire damage to different members, it was found that whenever any of the columns failed, progressive collapse of the frame would occur. Therefore, damages to columns should be prevented or the columns should be designed and constructed to allow for possible damage. If the beams are damaged, it is still possible for the damaged frame to achieve the reference fire resistance time of the undamaged structure (which is used as the criterion to accept that the damaged frame has sufficient robustness) by developing catenary action in the damaged beam. For this to happen, the…
Subjects/Keywords: 624.1; Robustness; Composite steel concrete structure; catenary action; Fire; Partial damage
Beshir, M. (2016). Robustness of composite framed structures in fire . (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-composite-framed-structures-in-fire(9c72a722-5b6a-477b-ac84-cd243ab73f34).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713557
Beshir, Moustafa. "Robustness of composite framed structures in fire." 2016. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-composite-framed-structures-in-fire(9c72a722-5b6a-477b-ac84-cd243ab73f34).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713557.
Beshir, Moustafa. "Robustness of composite framed structures in fire." 2016. Web. 22 Jan 2020.
Beshir M. Robustness of composite framed structures in fire. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2020 Jan 22]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-composite-framed-structures-in-fire(9c72a722-5b6a-477b-ac84-cd243ab73f34).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713557.
Beshir M. Robustness of composite framed structures in fire. [Doctoral Dissertation]. University of Manchester; 2016. Available from: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-composite-framed-structures-in-fire(9c72a722-5b6a-477b-ac84-cd243ab73f34).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.713557
3. Vessali, N. Compressive membrane action in reinforced concrete beams.
Degree: 2015, University of Technology, Sydney
► Research studies have demonstrated that membrane action is primarily a compressive load carrying mechanism that can significantly improves the load-bearing capacity of reinforced concrete beams… (more)
▼ Research studies have demonstrated that membrane action is primarily a compressive load carrying mechanism that can significantly improves the load-bearing capacity of reinforced concrete beams during extreme loading scenarios such as column loss. However, the behaviour of reinforced concrete (RC) beam assemblages under membrane action has not been thoroughly explored and therefore, the development of the compressive (arching) and tensile (catenary) membrane actions in RC beams should be investigated further by experimental and analytical studies. Membrane action is affected by various parameters such as compressive strength of the concrete, reinforcement ratio and transverse reinforcement of the beam. However; previously conducted researches indicate that compressive membrane (arching) action is not considerably influenced by reinforcement ratio which was shown to be the critical parameter in development of the tensile membrane (catenary) action. Also, both translational and rotational stiffness of end supports have significant influence on development of membrane action. Development of membrane action in RC members is typically associated with geometrical as well as material nonlinearities (including concrete cracking and crushing, reinforcing bar yielding and fracture) and due to these strong nonlinearities, most of the existing implicit finite element (FE) models and simplified analytical methods fail to adequately capture the compressive and tensile membrane behaviour of RC elements. The main focus of this research project is to experimentally and numerically investigate development of membrane action in RC beam assemblages. In the experimental program, influence of various parameters including concrete compressive strength, reinforcement bar arrangement and ratio and boundary conditions on the membrane response of RC beam assemblages following a column loss scenario are investigated. Furthermore, two different classes of nonlinear FE models, i.e. a 1D discrete frame and a continuum-based FE models are developed and data obtained from the experimental program are employed to verify and validate the developed FE models. Using a simplified approach, the influence of steel bar rupture is incorporated into the formulation of an existing flexibility-based frame element and it is shown that the proposed strategy has the ability to adequately model the rupture of steel bars and its implications at global level.
Subjects/Keywords: Compressive membrane action.; Reinforced concrete (RC) beams.; Compressive membrane (arching) action.; Tensile membrane (catenary) action.; Finite element (FE).; Nonlinear FE models.
Vessali, N. (2015). Compressive membrane action in reinforced concrete beams . (Thesis). University of Technology, Sydney. Retrieved from http://hdl.handle.net/10453/39180
Vessali, N. "Compressive membrane action in reinforced concrete beams." 2015. Thesis, University of Technology, Sydney. Accessed January 22, 2020. http://hdl.handle.net/10453/39180.
Vessali, N. "Compressive membrane action in reinforced concrete beams." 2015. Web. 22 Jan 2020.
Vessali N. Compressive membrane action in reinforced concrete beams. [Internet] [Thesis]. University of Technology, Sydney; 2015. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/10453/39180.
Vessali N. Compressive membrane action in reinforced concrete beams. [Thesis]. University of Technology, Sydney; 2015. Available from: http://hdl.handle.net/10453/39180
4. Albrifkani, Sherwan Mz Izzaddin. WHOLE RANGE BEHAVIOUR OF RESTRAINED REINFORCED CONCRETE BEAMS AND FRAMES IN FIRE.
► This thesis presents the results of a numerical investigation of the whole range, large deflection behaviour of axially and rotationally restrained RC beams and interactions… (more)
▼ This thesis presents the results of a numerical investigation of the whole range, large deflection behaviour of axially and rotationally restrained RC beams and interactions between beams and columns in RC frame structures exposed to fire. The dynamic explicit time integration algorithm implemented in the general finite element package ABAQUS/Explicit solver was used so as to overcome various modelling challenges including temporary instability, local failure of materials, non-convergence and long simulation time. Either load factoring or mass scaling may be used to speed up the simulation process. Validity of the proposed simulation model was checked by comparison of simulation results against relevant test results of restrained RC beams at ambient temperature and in fire. The validated ABAQUS/Explicit model was then used to conduct a comprehensive study of the effects of different levels of axial and rotational restraints on the whole range behaviour of RC beams in fire, including combined bending and compression due to restrained thermal expansion, bending failure, transition from compression to tension when catenary action develops and complete fracture of reinforcement at ultimate failure. The numerical results show that different bending failure modes (middle span sagging failure, end hogging failure due to fracture of tensile reinforcement, end hogging failure due to concrete crushing) can occur under different levels of boundary restraints. Furthermore, release of a large amount of energy during the rapid transition phase from compression to tension in a beam prevents formation of a three hinge mechanism in the beam under bending. The numerical results have also revealed that reliable catenary action develops at large deflections following bending failure only if bending failure is governed by compressive failure of concrete at the end supports whereby a continuous tension path in the beam can develop in the top reinforcement. To allow fire engineering practice to take into consideration the complex restrained RC beam behaviour in fire, a simplified calculation method has been developed and validated against the numerical simulation results. The proposed method is based on sectional analysis and meets the requirements of strain compatibility and force equilibrium. The validation study results have shown that the simplified method can satisfactorily predict the various key quantities of restrained beam axial force and beam deflection-fire exposure time relationships, with the simplified method generally giving results on the safe side. The validated explicit finite element model in ABAQUS was also used to investigate structural interactions between beams and columns within an RC frame structure with different fire exposure scenarios. When fire exposure involves beams and columns located in edge bays of a frame, catenary action cannot develop. Also due to thermal expansion of the connected beam, additional bending moments can generate in the columns. Furthermore, very large hogging moments can be induced at the… Advisors/Committee Members: YANG, ZHENJUN Z, Wang, Yong, Yang, Zhenjun.
Subjects/Keywords: Fire resistance; Explicit modelling; Restrained reinforced concrete beam; Catenary action; Reinforced concrete frame
Albrifkani, S. M. I. (2017). WHOLE RANGE BEHAVIOUR OF RESTRAINED REINFORCED CONCRETE BEAMS AND FRAMES IN FIRE . (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:311972
Albrifkani, Sherwan Mz Izzaddin. "WHOLE RANGE BEHAVIOUR OF RESTRAINED REINFORCED CONCRETE BEAMS AND FRAMES IN FIRE." 2017. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:311972.
Albrifkani, Sherwan Mz Izzaddin. "WHOLE RANGE BEHAVIOUR OF RESTRAINED REINFORCED CONCRETE BEAMS AND FRAMES IN FIRE." 2017. Web. 22 Jan 2020.
Albrifkani SMI. WHOLE RANGE BEHAVIOUR OF RESTRAINED REINFORCED CONCRETE BEAMS AND FRAMES IN FIRE. [Internet] [Doctoral dissertation]. University of Manchester; 2017. [cited 2020 Jan 22]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:311972.
Albrifkani SMI. WHOLE RANGE BEHAVIOUR OF RESTRAINED REINFORCED CONCRETE BEAMS AND FRAMES IN FIRE. [Doctoral Dissertation]. University of Manchester; 2017. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:311972
5. Albrifkani, Sherwan. Whole range behaviour of restrained reinforced concrete beams and frames in fire.
URL: https://www.research.manchester.ac.uk/portal/en/theses/whole-range-behaviour-of-restrained-reinforced-concrete-beams-and-frames-in-fire(95ff52f9-d90a-4873-8ef1-7ea301074e13).html  ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.764498
▼ This thesis presents the results of a numerical investigation of the whole range, large deflection behaviour of axially and rotationally restrained RC beams and interactions between beams and columns in RC frame structures exposed to fire. The dynamic explicit time integration algorithm implemented in the general finite element package ABAQUS/Explicit solver was used so as to overcome various modelling challenges including temporary instability, local failure of materials, non-convergence and long simulation time. Either load factoring or mass scaling may be used to speed up the simulation process. Validity of the proposed simulation model was checked by comparison of simulation results against relevant test results of restrained RC beams at ambient temperature and in fire. The validated ABAQUS/Explicit model was then used to conduct a comprehensive study of the effects of different levels of axial and rotational restraints on the whole range behaviour of RC beams in fire, including combined bending and compression due to restrained thermal expansion, bending failure, transition from compression to tension when catenary action develops and complete fracture of reinforcement at ultimate failure. The numerical results show that different bending failure modes (middle span sagging failure, end hogging failure due to fracture of tensile reinforcement, end hogging failure due to concrete crushing) can occur under different levels of boundary restraints. Furthermore, release of a large amount of energy during the rapid transition phase from compression to tension in a beam prevents formation of a three hinge mechanism in the beam under bending. The numerical results have also revealed that reliable catenary action develops at large deflections following bending failure only if bending failure is governed by compressive failure of concrete at the end supports whereby a continuous tension path in the beam can develop in the top reinforcement. To allow fire engineering practice to take into consideration the complex restrained RC beam behaviour in fire, a simplified calculation method has been developed and validated against the numerical simulation results. The proposed method is based on sectional analysis and meets the requirements of strain compatibility and force equilibrium. The validation study results have shown that the simplified method can satisfactorily predict the various key quantities of restrained beam axial force and beam deflection-fire exposure time relationships, with the simplified method generally giving results on the safe side. The validated explicit finite element model in ABAQUS was also used to investigate structural interactions between beams and columns within an RC frame structure with different fire exposure scenarios. When fire exposure involves beams and columns located in edge bays of a frame, catenary action cannot develop. Also due to thermal expansion of the connected beam, additional bending moments can generate in the columns. Furthermore, very large hogging moments can be induced at the…
Subjects/Keywords: Reinforced concrete frame; Fire resistance; Explicit modelling; Restrained reinforced concrete beam; Catenary action
Albrifkani, S. (2017). Whole range behaviour of restrained reinforced concrete beams and frames in fire . (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/whole-range-behaviour-of-restrained-reinforced-concrete-beams-and-frames-in-fire(95ff52f9-d90a-4873-8ef1-7ea301074e13).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.764498
Albrifkani, Sherwan. "Whole range behaviour of restrained reinforced concrete beams and frames in fire." 2017. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. https://www.research.manchester.ac.uk/portal/en/theses/whole-range-behaviour-of-restrained-reinforced-concrete-beams-and-frames-in-fire(95ff52f9-d90a-4873-8ef1-7ea301074e13).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.764498.
Albrifkani, Sherwan. "Whole range behaviour of restrained reinforced concrete beams and frames in fire." 2017. Web. 22 Jan 2020.
Albrifkani S. Whole range behaviour of restrained reinforced concrete beams and frames in fire. [Internet] [Doctoral dissertation]. University of Manchester; 2017. [cited 2020 Jan 22]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/whole-range-behaviour-of-restrained-reinforced-concrete-beams-and-frames-in-fire(95ff52f9-d90a-4873-8ef1-7ea301074e13).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.764498.
Albrifkani S. Whole range behaviour of restrained reinforced concrete beams and frames in fire. [Doctoral Dissertation]. University of Manchester; 2017. Available from: https://www.research.manchester.ac.uk/portal/en/theses/whole-range-behaviour-of-restrained-reinforced-concrete-beams-and-frames-in-fire(95ff52f9-d90a-4873-8ef1-7ea301074e13).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.764498
6. Sagiroglu, Serkan. Analytical and experimental evaluation of progressive collapse resistance of reinforced concrete structures.
Degree: PhD, Department of Civil and Environmental Engineering, 2012, Northeastern University
URL: http://hdl.handle.net/2047/d20002914
► Experimental and analytical studies are carried out on three full-scale actual reinforced concrete (RC) buildings to characterize system level resisting mechanisms against progressive collapse following… (more)
▼ Experimental and analytical studies are carried out on three full-scale actual reinforced concrete (RC) buildings to characterize system level resisting mechanisms against progressive collapse following an initial local damage. The results obtained from the analytical models are verified with the experimental data and important modeling issues, assumptions, and requirements for structural elements as well as infill walls are identified and discussed. In order to evaluate the effects of initial damage location on progressive collapse of structures, a seven-story RC building structure is designed. Using an analytical model of the structure based on the knowledge gained in this study, the structure is analyzed under 15 different initial damage scenarios.; None of the experimentally evaluated structures experienced full or partial collapse. Vierendeel frame action is found to be the dominant progressive collapse resisting mechanism following element removal in all evaluated structures. The seven-story building designed in this study is found to be susceptible to collapse under the initial damage scenario of top floor corner column removal and top floor middle column removal on its short edge. The capability of the structure to develop Vierendeel Frame Action is crucial in resisting progressive collapse. Structures are less susceptible to collapse if there are at least two floors (and connecting columns) above the removed column such that Vierendeel frame action can effectively develop. Vierendeel frame action can be characterized by double curvature deformations of beams, slabs, and columns. Such a deformed shape provides shear forces in beams and slabs required to redistribute gravity loads following column removal. The direction of bending moments in the elements in the vicinity of the removed column changes after column removal. A potential brittle failure mechanism is identified and described which can develop due to insufficient reinforcement and the change in the moment direction. It is shown that axial compressive force develops in beams and slabs due to their growth at small displacements. This axial force enhances the flexural capacities of floor elements (beams and slabs) and in turn improves the performance of the Vierendeel frame action considerably. In the building structures discussed above, the level of displacements and deformations were not large enough to develop Catenary action.; In order to study Catenary action response in RC structures, progressive collapse resistance of a scaled two-dimensional frame structure is studied experimentally and analytically. The frame experienced small deformations and resisted collapse after being subjected a column removal on its first floor. Following this test, the frame was also subjected to monotonically increasing displacement at the top of the removed column to further study the resisting mechanism(s). The Catenary action was observed experimentally and evaluated analytically.
Subjects/Keywords: Catenary action; Dynamic response; Load redistribution; Load resistance; Progressive collapse; Vierendeel frame action; Civil Engineering; Structural Engineering
Sagiroglu, S. (2012). Analytical and experimental evaluation of progressive collapse resistance of reinforced concrete structures . (Doctoral Dissertation). Northeastern University. Retrieved from http://hdl.handle.net/2047/d20002914
Sagiroglu, Serkan. "Analytical and experimental evaluation of progressive collapse resistance of reinforced concrete structures." 2012. Doctoral Dissertation, Northeastern University. Accessed January 22, 2020. http://hdl.handle.net/2047/d20002914.
Sagiroglu, Serkan. "Analytical and experimental evaluation of progressive collapse resistance of reinforced concrete structures." 2012. Web. 22 Jan 2020.
Sagiroglu S. Analytical and experimental evaluation of progressive collapse resistance of reinforced concrete structures. [Internet] [Doctoral dissertation]. Northeastern University; 2012. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/2047/d20002914.
Sagiroglu S. Analytical and experimental evaluation of progressive collapse resistance of reinforced concrete structures. [Doctoral Dissertation]. Northeastern University; 2012. Available from: http://hdl.handle.net/2047/d20002914
7. Elsawaf, Sherif Ahmed Elkarim Ibrahim Soliman. Robustness of connections to concrete-filled steel tubular columns under fire during heating and cooling.
URL: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-connections-to-concretefilled-steel-tubular-columns-under-fire-during-heating-and-cooling(b1ef6849-2d59-4e73-b0c9-c57d0293ec51).html  ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555530
► Joint behaviour in fire is currently one of the most important topics of research in structural fire resistance. The collapse of World Trade Center buildings… (more)
▼ Joint behaviour in fire is currently one of the most important topics of research in structural fire resistance. The collapse of World Trade Center buildings and the results of the Cardington full-scale eight storey steel framed building fire tests in the UK have demonstrated that steel joints are particularly vulnerable during the heating and cooling phases of fire. The main purpose of this research is to develop robust joints to CFT columns that are capable of providing very high rotational and tying resistances to make it possible for the connected beam to fully develop catenary action during the heating phase of fire attack and to retain integrity during the cooling phase of fire attack. This research employed the general finite element software ABAQUS to numerically model the behaviour of restrained structural subassemblies of steel beam to concrete filled tubular (CFT) columns and their joints in fire. For validation, this research compared the simulation and test results for 10 fire tests previously conducted at the University of Manchester. It was envisaged that catenary action in the connected beams at very large deflections would play an important role in ensuring robustness of steel framed structures in fire. Therefore, it was vital that the numerical simulations could accurately predict the structural behaviour at very large deflections. In particular, the transitional behaviour of the beam from compression to catenary action presented tremendous difficulties in numerical simulations due to the extremely high rate of deflection increase. This thesis will explain the methodology of a suitable simulation method, by introducing a pseudo damping factor. The comparison between the FE and the experimental results demonstrates that the 3-D finite element model is able to successfully simulate the fire tests. The validated ABAQUS model was then applied to conduct a thorough set of numerical studies to investigate methods of improving the survival temperatures under heating in fire of steel beams to concrete filled tubular (CFT) columns using reverse channel connection. This study investigated five different joint types of reverse channel connection: extended endplate, flush endplate, flexible endplate, hybrid flush/flexible endplate and hybrid extended/flexible endplate. The connection details investigated include reverse channel web thickness, bolt diameter and grade, using fire-resistant (FR) steel for different joint components (reverse channel, end plate and bolts) and joint temperature control. The effects of changing the applied beam and column loads were also considered. It is concluded that by adopting some of the joint details to improve the joint tensile strength and deformation capacity, it is possible for the beams to develop substantial catenary action to survive very high temperatures. This thesis also explains the implications on fire resistant design of the connected columns in order to resist the additional catenary force in the beam. The validated numerical model was also used to perform…
Subjects/Keywords: 624.1; connection; fire resistance; catenary action; numerical modelling;
Elsawaf, S. A. E. I. S. (2012). Robustness of connections to concrete-filled steel tubular columns under fire during heating and cooling . (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-connections-to-concretefilled-steel-tubular-columns-under-fire-during-heating-and-cooling(b1ef6849-2d59-4e73-b0c9-c57d0293ec51).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555530
Elsawaf, Sherif Ahmed Elkarim Ibrahim Soliman. "Robustness of connections to concrete-filled steel tubular columns under fire during heating and cooling." 2012. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-connections-to-concretefilled-steel-tubular-columns-under-fire-during-heating-and-cooling(b1ef6849-2d59-4e73-b0c9-c57d0293ec51).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555530.
Elsawaf, Sherif Ahmed Elkarim Ibrahim Soliman. "Robustness of connections to concrete-filled steel tubular columns under fire during heating and cooling." 2012. Web. 22 Jan 2020.
Elsawaf SAEIS. Robustness of connections to concrete-filled steel tubular columns under fire during heating and cooling. [Internet] [Doctoral dissertation]. University of Manchester; 2012. [cited 2020 Jan 22]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-connections-to-concretefilled-steel-tubular-columns-under-fire-during-heating-and-cooling(b1ef6849-2d59-4e73-b0c9-c57d0293ec51).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555530.
Elsawaf SAEIS. Robustness of connections to concrete-filled steel tubular columns under fire during heating and cooling. [Doctoral Dissertation]. University of Manchester; 2012. Available from: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-connections-to-concretefilled-steel-tubular-columns-under-fire-during-heating-and-cooling(b1ef6849-2d59-4e73-b0c9-c57d0293ec51).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555530
8. Lee, Seungjea. Robustness of reinforced concrete framed building at elevated temperatures.
URL: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-reinforced-concrete-framed-building-at-elevated-temperatures(db90ad82-86b5-4ba3-9ef1-42e7004b4b34).html  ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727909
► This thesis presents the results of a research programme to investigate the behaviour and robustness of reinforced concrete (RC) frames in fire. The research was… (more)
▼ This thesis presents the results of a research programme to investigate the behaviour and robustness of reinforced concrete (RC) frames in fire. The research was carried out through numerical simulations using the commercial finite element analysis package TNO DIANA. The main focus of the project is the large deflection behaviour of restrained reinforced concrete beams, in particular the development of catenary action, because this behaviour is the most important factor that influences the frame response under accidental loading. This research includes four main parts as follows: (1) validation of the simulation model; (2) behaviour of axially and rotationally restrained RC beams at elevated temperatures; (3) derivation of an analytical method to estimate the key quantities of restrained RC beam behaviour at elevated temperatures; (4) response and robustness of RC frame structures with different extents of damage at elevated temperatures. The analytical method has been developed to estimate the following three quantities: when the axial compression force in the restrained beam reaches the maximum; when the RC beams reach bending limits (axial force = 0) and when the beams finally fail. To estimate the time to failure, which is initiated by the fracture of reinforcement steel at the catenary action stage, a regression equation is proposed to calculate the maximum deflections of RC beams, based on an analysis of the reinforcement steel strain distributions at failure for a large number of parametric study results. A comparison between the analytical and simulation results indicates that the analytical method gives reasonably good approximations to the numerical simulation results. Based on the frame simulation results, it has been found that if a member is completely removed from the structure, the structure is unlikely to be able to develop an alternative load carrying mechanism to ensure robustness of the structure. This problem is particularly severe when a corner column is removed. However, it is possible for frames with partially damaged columns to achieve the required robustness in fire, provided the columns still have sufficient resistance to allow the beams to develop some catenary action. This may be possible if the columns are designed as simply supported columns, but have some reserves of strength in the frame due to continuity. Merely increasing the reinforcement steel area or ductility (which is difficult to do) would not be sufficient. However, increasing the cover thickness of the reinforcement steel to slow down the temperature increase is necessary.
Subjects/Keywords: 624.1; tying method; level of axial restraints; catenary action; elevated temperatures; reinforced concrete building; Robustness; fire engineering
Lee, S. (2016). Robustness of reinforced concrete framed building at elevated temperatures . (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-reinforced-concrete-framed-building-at-elevated-temperatures(db90ad82-86b5-4ba3-9ef1-42e7004b4b34).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727909
Lee, Seungjea. "Robustness of reinforced concrete framed building at elevated temperatures." 2016. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-reinforced-concrete-framed-building-at-elevated-temperatures(db90ad82-86b5-4ba3-9ef1-42e7004b4b34).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727909.
Lee, Seungjea. "Robustness of reinforced concrete framed building at elevated temperatures." 2016. Web. 22 Jan 2020.
Lee S. Robustness of reinforced concrete framed building at elevated temperatures. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2020 Jan 22]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-reinforced-concrete-framed-building-at-elevated-temperatures(db90ad82-86b5-4ba3-9ef1-42e7004b4b34).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727909.
Lee S. Robustness of reinforced concrete framed building at elevated temperatures. [Doctoral Dissertation]. University of Manchester; 2016. Available from: https://www.research.manchester.ac.uk/portal/en/theses/robustness-of-reinforced-concrete-framed-building-at-elevated-temperatures(db90ad82-86b5-4ba3-9ef1-42e7004b4b34).html ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.727909
9. Jamshidi,Amirhoushang. Steel Shear Connections in Composite Frames Subject to Progressive Collapse.
Degree: PhD, Department of Civil and Environmental Engineering, 2016, University of Alberta
URL: https://era.library.ualberta.ca/files/c4x51hj092
► The susceptibility of structures to extensive collapse when subjected to a localised failure due to an extreme loading event has in recent years gained considerable… (more)
▼ The susceptibility of structures to extensive collapse when subjected to a localised failure due to an extreme loading event has in recent years gained considerable research attention. The scenario most often used to assess such performance, either experimentally or through finite element simulation, is the loss of a column, requiring the floor system to bridge across two building bays with the aid of arching and catenary actions. When a column is abruptly disengaged by an abnormal load, the resulting double-span beam must bridge over the removed column by developing a new equilibrium path to redistribute the load to the adjacent elements. This severe damage in a steel gravity frame, which is designed to carry primarily gravity loads, creates significant demands on shear connections. The response of steel shear connections as a component of steel gravity composite frame systems under the column removal scenario is still largely unknown due to the complex interaction between the slab and the steel framework at large deflections. While the slab itself can participate in maintaining the integrity of the overall floor system, its presence amplifies the demand on the steel connections after experiencing initial flexural action. This research investigated the behaviour of steel shear connections in composite frames under a simulated progressive collapse scenario. The research objectives, experimental protocols, and the most significant conclusions drawn from test observations are discussed. The present study describes the details of a comprehensive experimental and numerical program that has been completed to assess the behaviour of connections in composite floor construction by evaluating the failure mode, load carrying mechanisms, strength, and ductility of the connections. An experimental program consisting of 17 full-scale physical tests was performed on connections that included shear tabs and double angles. A variety of parameters were considered, including the connection type, connection depth, connection material thickness, and notional beam span. A testing procedure based on the proposed loading protocols was developed and executed on connections to simulate demands and deformations expected in a composite floor system under a column removal scenario. The second part of this research consisted of comprehensive finite element modelling and analysis techniques. Models were validated using the test results. They were also expanded to investigate the effects of critical parameters on the performance of shear connections in composite frames. Detailed three-dimensional prototype simulations were evaluated and compared with the simplified finite element models and physical tests. The overall capacity of the prototype systems was evaluated and compared with the integrity requirements stipulated in current Canadian and US building codes and design guidelines. Design recommendations based on the experiments and finite element models are proposed for calculating the capacity and ductility of shear connections in composite…
Subjects/Keywords: Composite Frame; Catenary Action; Composite Construction System; Double Angle; Arching Action; Steel Shear Connections; Concrete Slab; Compressive Ring; Progressive Collapse; Disproportionate Collapse; Shear Tab
Jamshidi,Amirhoushang. (2016). Steel Shear Connections in Composite Frames Subject to Progressive Collapse . (Doctoral Dissertation). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/c4x51hj092
Author name may be incomplete
Jamshidi,Amirhoushang. "Steel Shear Connections in Composite Frames Subject to Progressive Collapse." 2016. Doctoral Dissertation, University of Alberta. Accessed January 22, 2020. https://era.library.ualberta.ca/files/c4x51hj092.
Jamshidi,Amirhoushang. "Steel Shear Connections in Composite Frames Subject to Progressive Collapse." 2016. Web. 22 Jan 2020.
Jamshidi,Amirhoushang. Steel Shear Connections in Composite Frames Subject to Progressive Collapse. [Internet] [Doctoral dissertation]. University of Alberta; 2016. [cited 2020 Jan 22]. Available from: https://era.library.ualberta.ca/files/c4x51hj092.
Jamshidi,Amirhoushang. Steel Shear Connections in Composite Frames Subject to Progressive Collapse. [Doctoral Dissertation]. University of Alberta; 2016. Available from: https://era.library.ualberta.ca/files/c4x51hj092
10. Chen, Lu. Robustness in fire of steel framed structures with realistic connections.
URL: https://www.research.manchester.ac.uk/portal/en/theses/robustness-in-fire-of-steel-framed-structures-with-realistic-connections(fcf4d94b-56f4-42bc-b20a-e2e497d4c14a).html  ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568652
► Joints are the most critical elements in a steel framed structure. In most design guides or codes, the joints are assumed to a have higher… (more)
▼ Joints are the most critical elements in a steel framed structure. In most design guides or codes, the joints are assumed to a have higher fire resistance than the connected structural members because of the lower temperatures in the joints. However, in severe fire conditions, a connected beam's temperature may be higher than its limiting temperature and the beam may develop catenary action when the beam's axial shortening from large deflections becomes greater than the beam's thermal expansion. This beam catenary action force could fracture the joints, increasing the risk of progressive collapse. This research focuses on the interaction between joints and the connected steel beams and columns in steel framed structures in fire, including how the behaviour of a joint-beam assembly may be efficiently analyzed and how the joints may be constructed to achieve high degrees of catenary action. Three methods of simulating the joint behaviour in fire have been developed and implemented in the commercial finite element software ABAQUS. In the first modelling method, all structural members, including the connections, were simulated using detailed solid elements to enable detailed behaviour of the structure to be faithfully represented. In the second method, the columns were represented by conventional line (beam) elements, the joints were represented using springs (Connector Elements) based on the component based method, and the beam was modelled using solid elements. In the third method, the joints were modelled using springs as in the second method and the beam and columns were simulated using line (beam) elements. As expected, the detailed simulation method was extremely time-consuming, but was able to produce detailed and accurate results. The simulation results from the second and third methods contained some inaccuracies, but depending on the simulation objective, their simulation results may be acceptable. In particular, the third simulation method was very efficient, suitable for simulating complete frame structures under very large deflections in fire. The first method (detailed finite element method) was then used to investigate how to change the joint details to increase the survivability of restrained steel beams and beam-column assemblies at high temperatures since it enables detailed behaviour of the structure to be faithfully represented. It is found that by improving joint deformation capacity, in particular, using extended endplate connection with fire resistant bolts, very high temperatures can be resisted. The frame robustness in fire was investigated using the third simulation method to save computation time. The simulation structure was three-bay by three-floor and different scenarios of fire location, fire spread and initial structural damage were considered. The simulation results show that once failure of a column occurs, progressive collapse of the structure could be easily triggered and it would be rather futile to only enhance the joint capacity. Therefore, in addition to the measures of improving…
Subjects/Keywords: 624.1; Joint; beam; column; frame; detailed finite element method; component based method; catenary action; limiting temperature; fire resistant bolt; fire resistant steel; survivability; robustness.
Chen, L. (2013). Robustness in fire of steel framed structures with realistic connections . (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/robustness-in-fire-of-steel-framed-structures-with-realistic-connections(fcf4d94b-56f4-42bc-b20a-e2e497d4c14a).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568652
Chen, Lu. "Robustness in fire of steel framed structures with realistic connections." 2013. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. https://www.research.manchester.ac.uk/portal/en/theses/robustness-in-fire-of-steel-framed-structures-with-realistic-connections(fcf4d94b-56f4-42bc-b20a-e2e497d4c14a).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568652.
Chen, Lu. "Robustness in fire of steel framed structures with realistic connections." 2013. Web. 22 Jan 2020.
Chen L. Robustness in fire of steel framed structures with realistic connections. [Internet] [Doctoral dissertation]. University of Manchester; 2013. [cited 2020 Jan 22]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/robustness-in-fire-of-steel-framed-structures-with-realistic-connections(fcf4d94b-56f4-42bc-b20a-e2e497d4c14a).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568652.
Chen L. Robustness in fire of steel framed structures with realistic connections. [Doctoral Dissertation]. University of Manchester; 2013. Available from: https://www.research.manchester.ac.uk/portal/en/theses/robustness-in-fire-of-steel-framed-structures-with-realistic-connections(fcf4d94b-56f4-42bc-b20a-e2e497d4c14a).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568652
11. Elsawaf, Sherif Ahmed Elkarim ibrahim soliman. ROBUSTNESS OF CONNECTIONS TO CONCRETE-FILLED STEEL TUBULAR COLUMNS UNDER FIRE DURING HEATING AND COOLING.
► ABSTRACTJoint behaviour in fire is currently one of the most important topics of research in struc-tural fire resistance. The collapse of World Trade Center buildings… (more)
▼ ABSTRACTJoint behaviour in fire is currently one of the most important topics of research in struc-tural fire resistance. The collapse of World Trade Center buildings and the results of the Cardington full-scale eight storey steel framed building fire tests in the UK have dem-onstrated that steel joints are particularly vulnerable during the heating and cooling phases of fire. The main purpose of this research is to develop robust joints to CFT col-umns that are capable of providing very high rotational and tying resistances to make it possible for the connected beam to fully develop catenary action during the heating phase of fire attack and to retain integrity during the cooling phase of fire attack.This research employed the general finite element software ABAQUS to numerically model the behaviour of restrained structural subassemblies of steel beam to concrete filled tubular (CFT) columns and their joints in fire. For validation, this research com-pared the simulation and test results for 10 fire tests previously conducted at the Univer-sity of Manchester. It was envisaged that catenary action in the connected beams at very large deflections would play an important role in ensuring robustness of steel framed structures in fire. Therefore, it was vital that the numerical simulations could accurately predict the structural behaviour at very large deflections. In particular, the transitional behaviour of the beam from compression to catenary action presented tremendous diffi-culties in numerical simulations due to the extremely high rate of deflection increase. This thesis will explain the methodology of a suitable simulation method, by introduc-ing a pseudo damping factor. The comparison between the FE and the experimental re-sults demonstrates that the 3-D finite element model is able to successfully simulate the fire tests. The validated ABAQUS model was then applied to conduct a thorough set of numerical studies to investigate methods of improving the survival temperatures under heating in fire of steel beams to concrete filled tubular (CFT) columns using reverse channel con-nection. This study investigated five different joint types of reverse channel connection: extended endplate, flush endplate, flexible endplate, hybrid flush/flexible endplate and hybrid extended/flexible endplate. The connection details investigated include reverse channel web thickness, bolt diameter and grade, using fire-resistant (FR) steel for dif-ferent joint components (reverse channel, end plate and bolts) and joint temperature control. The effects of changing the applied beam and column loads were also consid-ered. It is concluded that by adopting some of the joint details to improve the joint ten-sile strength and deformation capacity, it is possible for the beams to develop substan-tial catenary action to survive very high temperatures. This thesis also explains the implications on fire resistant design of the connected columns in order to resist the addi-tional catenary force in the beam.The validated numerical model was also… Advisors/Committee Members: Wang, Yong.
Subjects/Keywords: connection, fire resistance, catenary action, numerical modelling,; concrete filled tubes, reverse channel connection, cooling, robustness
…in the column caused by catenary action force Mp - Column bending moment resistance at… …tying resistances to make it possible for the connected beam to fully develop catenary action… …Manchester. It was envisaged that catenary action in the connected beams at very large deflections… …compression to catenary action presented tremendous difficulties in numerical simulations due to the… …capacity, it is possible for the beams to develop substantial catenary action to survive very…
Elsawaf, S. A. E. i. (2012). ROBUSTNESS OF CONNECTIONS TO CONCRETE-FILLED STEEL TUBULAR COLUMNS UNDER FIRE DURING HEATING AND COOLING . (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:163632
Elsawaf, Sherif Ahmed Elkarim ibrahim. "ROBUSTNESS OF CONNECTIONS TO CONCRETE-FILLED STEEL TUBULAR COLUMNS UNDER FIRE DURING HEATING AND COOLING." 2012. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:163632.
Elsawaf, Sherif Ahmed Elkarim ibrahim. "ROBUSTNESS OF CONNECTIONS TO CONCRETE-FILLED STEEL TUBULAR COLUMNS UNDER FIRE DURING HEATING AND COOLING." 2012. Web. 22 Jan 2020.
Elsawaf SAEi. ROBUSTNESS OF CONNECTIONS TO CONCRETE-FILLED STEEL TUBULAR COLUMNS UNDER FIRE DURING HEATING AND COOLING. [Internet] [Doctoral dissertation]. University of Manchester; 2012. [cited 2020 Jan 22]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:163632.
Elsawaf SAEi. ROBUSTNESS OF CONNECTIONS TO CONCRETE-FILLED STEEL TUBULAR COLUMNS UNDER FIRE DURING HEATING AND COOLING. [Doctoral Dissertation]. University of Manchester; 2012. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:163632
12. Lee, Seungjea. ROBUSTNESS OF REINFORCED CONCRETE FRAMED BUILDING AT ELEVATED TEMPERATURES.
▼ This thesis presents the results of a research programme to investigate the behaviour and robustness of reinforced concrete (RC) frames in fire. The research was carried out through numerical simulations using the commercial finite element analysis package TNO DIANA. The main focus of the project is the large deflection behaviour of restrained reinforced concrete beams, in particular the development of catenary action, because this behaviour is the most important factor that influences the frame response under accidental loading. This research includes four main parts as follows: (1) validation of the simulation model; (2) behaviour of axially and rotationally restrained RC beams at elevated temperatures; (3) derivation of an analytical method to estimate the key quantities of restrained RC beam behaviour at elevated temperatures; (4) response and robustness of RC frame structures with different extents of damage at elevated temperatures.The analytical method has been developed to estimate the following three quantities: when the axial compression force in the restrained beam reaches the maximum; when the RC beams reach bending limits (axial force = 0) and when the beams finally fail. To estimate the time to failure, which is initiated by the fracture of reinforcement steel at the catenary action stage, a regression equation is proposed to calculate the maximum deflections of RC beams, based on an analysis of the reinforcement steel strain distributions at failure for a large number of parametric study results. A comparison between the analytical and simulation results indicates that the analytical method gives reasonably good approximations to the numerical simulation results.Based on the frame simulation results, it has been found that if a member is completely removed from the structure, the structure is unlikely to be able to develop an alternative load carrying mechanism to ensure robustness of the structure. This problem is particularly severe when a corner column is removed. However, it is possible for frames with partially damaged columns to achieve the required robustness in fire, provided the columns still have sufficient resistance to allow the beams to develop some catenary action. This may be possible if the columns are designed as simply supported columns, but have some reserves of strength in the frame due to continuity. Merely increasing the reinforcement steel area or ductility (which is difficult to do) would not be sufficient. However, increasing the cover thickness of the reinforcement steel to slow down the temperature increase is necessary. Advisors/Committee Members: Wang, Yong.
Subjects/Keywords: Robustness; reinforced concrete building; fire engineering; catenary action; elevated temperatures; level of axial restraints; tying method
…reinforced concrete beams, in particular the development of catenary action, because this behaviour… …which is initiated by the fracture of reinforcement steel at the catenary action stage, a… …resistance to allow the beams to develop some catenary action. This may be possible if the columns… …the axially restrained beam under catenary action may survive much higher temperatures than… …plastic hinge, accompanied by beam runaway deflection. Page 19 (a) Catenary action…
Lee, S. (2016). ROBUSTNESS OF REINFORCED CONCRETE FRAMED BUILDING AT ELEVATED TEMPERATURES . (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:303448
Lee, Seungjea. "ROBUSTNESS OF REINFORCED CONCRETE FRAMED BUILDING AT ELEVATED TEMPERATURES." 2016. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:303448.
Lee S. ROBUSTNESS OF REINFORCED CONCRETE FRAMED BUILDING AT ELEVATED TEMPERATURES. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2020 Jan 22]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:303448.
Lee S. ROBUSTNESS OF REINFORCED CONCRETE FRAMED BUILDING AT ELEVATED TEMPERATURES. [Doctoral Dissertation]. University of Manchester; 2016. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:303448
13. Harry, Ofonime Akpan. Behaviour of reinforced concrete frame structure against progressive collapse.
Degree: PhD, 2018, University of Edinburgh
► A structure subjected to extreme load due to explosion or human error may lead to progressive collapse. One of the direct methods specified by design… (more)
▼ A structure subjected to extreme load due to explosion or human error may lead to progressive collapse. One of the direct methods specified by design guidelines for assessing progressive collapse is the Alternate Load Path method which involves removal of a structural member and analysing the structure to assess its potential of bridging over the removed member without collapse. The use of this method in assessing progressive collapse therefore requires that the vertical load resistance function of the bridging beam assembly, which for a typical laterally restrained reinforced concrete (RC) beams include flexural, compressive arching action and catenary action, be accurately predicted. In this thesis, a comprehensive study on a reliable prediction of the resistance function for the bridging RC beam assemblies is conducted, with a particular focus on a) the arching effect, and b) the catenary effect considering strength degradations. A critical analysis of the effect of axial restraint, flexural reinforcement ratio and span-depth ratio on compressive arching action are evaluated in quantitative terms. A more detailed theoretical model for the prediction of load-displacement behaviour of RC beam assemblies within the compressive arching response regime is presented. The proposed model takes into account the compounding effect of bending and arching from both the deformation and force points of view. Comparisons with experimental results show good agreement. Following the compressive arching action, catenary action can develop at a much larger displacement regime, and this action could help address collapse. A complete resistance function should adequately account for the catenary action as well as the arching effect. To this end, a generic catenary model which takes into consideration the strength degradation due to local failure events (e.g. rupture of bottom rebar or fracture of a steel weld) and the eventual failure limit is proposed. The application of the model in predicting the resistance function in beam assemblies with strength degradations is discussed. The validity of the proposed model is checked against predictions from finite element model and experimental tests. The result indicate that strength degradation can be accurately captured by the model. Finally, the above developed model framework is employed in investigative studies to demonstrate the application of the resistance functions in a dynamic analysis procedure, as well as the significance of the compressive arching effect and the catenary action in the progressive collapse resistance in different designs. The importance of an accurate prediction of the arching effect and the limiting displacement for the catenary action is highlighted.
Subjects/Keywords: Alternate Load Path; progressive collapse; compressive arching action; catenary action; reinforced concrete beams; strength degradations; load-displacement behaviour; theoretical models
…39 2.7.2 Analytical studies on catenary action… …168 Chapter 6: Simplified theoretical model for prediction of catenary action… …174 6.3.2 Transient stage/catenary action stage… …204 6.7.4 Failure criteria during catenary action… …221 Figure 7.10: Strain damage contour during the catenary action stage (middle column…
Harry, O. A. (2018). Behaviour of reinforced concrete frame structure against progressive collapse . (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/29623
Harry, Ofonime Akpan. "Behaviour of reinforced concrete frame structure against progressive collapse." 2018. Doctoral Dissertation, University of Edinburgh. Accessed January 22, 2020. http://hdl.handle.net/1842/29623.
Harry, Ofonime Akpan. "Behaviour of reinforced concrete frame structure against progressive collapse." 2018. Web. 22 Jan 2020.
Harry OA. Behaviour of reinforced concrete frame structure against progressive collapse. [Internet] [Doctoral dissertation]. University of Edinburgh; 2018. [cited 2020 Jan 22]. Available from: http://hdl.handle.net/1842/29623.
Harry OA. Behaviour of reinforced concrete frame structure against progressive collapse. [Doctoral Dissertation]. University of Edinburgh; 2018. Available from: http://hdl.handle.net/1842/29623
▼ Joints are the most critical elements in a steel framed structure. In most design guides or codes, the joints are assumed to a have higher fire resistance than the connected structural members because of the lower temperatures in the joints. However, in severe fire conditions, a connected beam's temperature may be higher than its limiting temperature and the beam may develop catenary action when the beam's axial shortening from large deflections becomes greater than the beam's thermal expansion. This beam catenary action force could fracture the joints, increasing the risk of progressive collapse. This research focuses on the interaction between joints and the connected steel beams and columns in steel framed structures in fire, including how the behaviour of a joint-beam assembly may be efficiently analyzed and how the joints may be constructed to achieve high degrees of catenary action. Three methods of simulating the joint behaviour in fire have been developed and implemented in the commercial finite element software ABAQUS. In the first modelling method, all structural members, including the connections, were simulated using detailed solid elements to enable detailed behaviour of the structure to be faithfully represented. In the second method, the columns were represented by conventional line (beam) elements, the joints were represented using springs (Connector Elements) based on the component based method, and the beam was modelled using solid elements. In the third method, the joints were modelled using springs as in the second method and the beam and columns were simulated using line (beam) elements. As expected, the detailed simulation method was extremely time-consuming, but was able to produce detailed and accurate results. The simulation results from the second and third methods contained some inaccuracies, but depending on the simulation objective, their simulation results may be acceptable. In particular, the third simulation method was very efficient, suitable for simulating complete frame structures under very large deflections in fire. The first method (detailed finite element method) was then used to investigate how to change the joint details to increase the survivability of restrained steel beams and beam-column assemblies at high temperatures since it enables detailed behaviour of the structure to be faithfully represented. It is found that by improving joint deformation capacity, in particular, using extended endplate connection with fire resistant bolts, very high temperatures can be resisted. The frame robustness in fire was investigated using the third simulation method to save computation time. The simulation structure was three-bay by three-floor and different scenarios of fire location, fire spread and initial structural damage were considered. The simulation results show that once failure of a column occurs, progressive collapse of the structure could be easily triggered and it would be rather futile to only enhance the joint capacity. Therefore, in addition to the measures of improving… Advisors/Committee Members: Wang, Yong.
Subjects/Keywords: Joint; beam; column; frame; detailed finite element method; component based method; catenary action; limiting temperature; fire resistant bolt; fire resistant steel; survivability; robustness.
…moment in pure catenary action… …axially loaded in addition to bending moment due to beam catenary action.)… …temperature may be higher than its limiting temperature and the beam may develop catenary action… …thermal expansion. This beam catenary action force could fracture the joints, increasing the… …to achieve high degrees of catenary action. Three methods of simulating the joint behaviour…
Chen, L. (2013). ROBUSTNESS IN FIRE OF STEEL FRAMED STRUCTURES WITH REALISTIC CONNECTIONS . (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:187551
Chen, Lu. "ROBUSTNESS IN FIRE OF STEEL FRAMED STRUCTURES WITH REALISTIC CONNECTIONS." 2013. Doctoral Dissertation, University of Manchester. Accessed January 22, 2020. http://www.manchester.ac.uk/escholar/uk-ac-man-scw:187551.
Chen L. ROBUSTNESS IN FIRE OF STEEL FRAMED STRUCTURES WITH REALISTIC CONNECTIONS. [Internet] [Doctoral dissertation]. University of Manchester; 2013. [cited 2020 Jan 22]. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:187551.
Chen L. ROBUSTNESS IN FIRE OF STEEL FRAMED STRUCTURES WITH REALISTIC CONNECTIONS. [Doctoral Dissertation]. University of Manchester; 2013. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:187551