PRECAST CONCRETE SHEAR WALL CONNECTIONS FOR SEISMIC ZONES
The precast concrete shear wall system is becoming very popular in North America for low, medium, and highrise construction due to the economical advantages possible with 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 the last two phases of a six-year research program conducted to investigate the behaviour and the capacity of fIfteen connection configurations used for precast load-bearing shear wall panels subjected to monotonic shear loading and large reversed cyclic loading conditions. Connection configurations include 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 two types of dry-packed multiple shear keys. The research also include connections which support hollow-core slab with and without post-tensioning. The performance of new innovative connections, such as partial or complete debonding of the reinforcement continuity and the use of energy dissipating mechanical connections for the continuity reinforcement, were also examined. Three different levels of load normal to the connection to simulate the effects of gravity load were used. The research fmdings 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 Doctoral Candidate, Civil Engineering Departmeht, University of Manitoba 2 Associate Dean of Engineering and Professor, University of Manitoba PRECAST CONCRETE SHEAR WALL CONNECTIONS FOR SEISMIC ZONES K.A. Soudki and S.H. Rizkalla
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
Behavior and Design of Shear Connections for Loadbearing Wall Panels
D inring the past decade, use of precast loadbearing shear wall panels for high rise construction has become very popular due to the high quality control achieved at the precast concrete manufacturing plant and the ease of panel assembly and erection at the project site (Fig. 1). In the structure, the precast panels are tied together using continuity reinforcement bars and mechanical shear connectors. The gap between the panels, which is required for alignment, is normally filled with a dry pack grout. This grouting system eliminates the use of falsework and minimizes the use of temporary supports. Current design sources'3 provide only limited information about the behavior and ultimate shear carrying capacity of the connections described in this paper. The information available in the literaturelo mainly describes the shear friction mechanism and the dowel action of initially cracked concrete to concrete surfaces. The results of such studies cannot be directly applicable to the predescribed connections due to the presence of the dry pack grout layer between the two concrete surfaces.