DESIGN AND BEHAVIOUR OF DRY PRECAST CONNECTIONS
This research proposes a precast RCC dapped end connection between beams and corbel columns using PCI design codes. Recently, precast construction has gained popularity amongst design consultants, contractors and researchers due higher quality control, lesser construction time and ease of implementation. Private investors and policy makers are keen to invest in this sector for better design and construction techniques. The research carries out an in-depth survey of the literature to identify the most appropriate connection type based on structural integrity, lateral stability and robustness under gravity loads. The proposed beam is a dapped beam connected to the column using a reinforced dowel bar passing through the sleeves of the beam into the column’s corbel. Loading conditions, design requirements and detailing of steel reinforcement is in accordance with PCI code. In the first step, a preliminary design of the connection is performed by manual calculations followed an analytical approach. Next, each member is assessed individually to optimize the overall integrity of the connection. The dapped beam is analyzed in a Finite Element Software Package named, Abaqus CAE, for different cross-sections, a/d ratios and compressive strengths. The results are critically reviewed and analyzed. Then, the corbel and the column are analyzed using Tekla Tedd software package. The results show that the dapped beams have minimum deflection and maximum load bearing capacity when the a/d ratio is less than 1 and the compressive strength is higher. It is noted that upon failure, the cracks initiated at an angle of 45 degrees, making the connection vulnerable to failure at the re-entrant corner. The maximum allowable load were approximately 72kips along with a deflection of 0.3inches (a/d ratio 0.76) which were within the allowable limit. Similarly, the maximum shear strength computed was 60kips and it decreased as a/d ratios were increased to 1.5 to a magnitude of approximately 43kips. For the future work, this work can be applied to the construction of high-rise buildings under seismic and wind loads. It is intended that this study will benefit design consultants, contractors and researcher in improving their pre-cast design and concepts.