CONNECTIONS FOR PRECAST CONCRETE PANELS USED FOR HIGH RISE STRUCTURES
Precast load-bearing shear wall panels are used extensively for high-rise construction because of the ease and speed of assembly, and the high quality of the precast panels. The connections between panels are extremely important since they affect both the speed of erection and the overall integrity of the structure. This paper presents the results of a five-year research program conducted to investigate the behaviour and the capacity of nine connection configurations used for precast load-bearing shear wall panels subjected to monotonic shear loading. The paper also includes results of dry-packed connections subjected to reversed cyclic loads equivalent to earthquake loads. Connection configurations include two types of dry-packed multiple shear keys, dry-packed plain surface, dry-packed plain surface with continuity reinforcement, dry-packed with two types of mechanical shear connectors in addition to the continuity bars, dry-packed with post-tensioning, and connections which support hollow-core slab with and without post-tensioning. Three different levels of load normal to the connection were used to determine the effects of gravity load. Rational mathematical models were developed to predict the shear capacity of the connections at the maximum and ultimate limit states. These models were found to be in good agreement with the experimental results. The research findings of this investigation were implemented in the design and construction of three 32-stories apartment buildings in Winnipeg, Manitoba. The connections considered in this study provided significant savings in construction time and cost. 1 Professor, Civil Engineering Department, University of Manitoba 2 Graduate Student, Civil Engineering Department, University of Manitoba 3 Doctoral Candidate, Civil Engineering Department, University of Manitoba Rizkalla West Soudki, Connections for Precast Concrete Panels CONNECTIONS FOR PRECAST CONCRETE PANELS USED FOR HIGHRISE STRUCTURES S.H. Rizkalla, J. West and K.A. Soudk
Horizontal Post-Tensioned Connections for Precast Concrete Load bearing Shear Wall Panels
This paper presents the results of nine prototype specimens tested to investigate the behavior and capacity of post-tensioned horizontal connections typically used for precast loadbearing shear wall panels subjected to monotonic shear loading. Shear walls supporting hollow-core floor slabs were included. Two different levels of load normal to the connection were used to simulate the effects of gravity and permanent loading conditions. Test results were used to refine and calibrate rational mathematical models developed to predict the maximum shear capacity and the nominal shear strength of the connection. Various failure mechanisms are presented and discussed. A numerical design example is included to show the application of the proposed mathematical model. concrete construction adverse weather con high concrete shear and transverse
Convergence Anatomization of Aquaculture Production in Leading Fish-Producing Countries During the Period of 1997-2013
Growth and national importance of aquaculture production is empirically assessed as an important indicator of development. The present article aims to test whether the major aquaculture producing countries of the world are converging over time. The authors have applied the absolute and conditional beta convergence and sigma convergence approaches on the data of FAO for the period 1997-2013. The results show that there is an absolute beta convergence and sigma convergence among 25 major aquaculture producing countries; negative sign of coefficient of conditional beta convergence with per capita income is also noticed. It implies, the growth rates of aquaculture for developed nations are declining with rise in per capita income and backward fish-intensive countries are catching up with the giant producers like China and India. The cross-country variations are also going down which means that the countries' development gaps are getting narrowed by means of growth of aquaculture resources.