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
Accurate measurements of output characteristics and detonations of motorbike high-speed racing engine and their optimization at actual atmospheric conditions and combusted mixture composition
Abstract At a motorbike high speed racing engine there is very important an output engine characteristics which depends significantly on a detonation combustion rate, atmospheric conditions and a combusted mixture composition. The combustion process has got a relevant influence on a wear degree of main engine parts or on their damage eventually. The detonation combustion rate is very important because this kind of burning can be not only destructive but a useful phenomenon, as well. If the process of detonation burning is kept on a certain level, it can help significantly to the next increasing of an engine power output. In this article there is described the measurements of output characteristics of a high-speed racing engine which were performed by means of a data-recording system and the detonation combustion was evaluated using a quantitative method. The actual values of atmospheric conditions and the mixture composition were added to the measured values. Then the obtained values are compared visually with a damage degree of an engine piston caused by the detonation burning. The result is a limit value expressed in a number of detonation units related to a run distance interval of the vehicle driven by the high-speed racing engine. In framework of this run distance interval there is the process of detonation burning profitable. As well as it increases an engine power output and together it is not destructive with regard to engine design parts.