STATIC AND DYNAMIC PERFORMANCE OF DIRECT HYBRID CONNECTIONS OF CROSS-LAMINATED TIMBER WITH STEEL, CONCRETE AND LAMINATED STRAND LUMBER COMPOSITES

Abstract

HYBRID MULTISTORY BUILDINGS ARE EVERY DAY MORE COMMON IN THE CONSTRUCTION INDUSTRY, AND IN THE CASE OF TALL WOODEN BUILDINGS, ADVANCED TIMBER COMPOSITES ARE CUSTOMARILY MIXED WITH CONCRETE AND STEEL MATERIALS TO ENHANCE LATERAL STIFFNESS AND STRENGTH AMONG OTHER MECHANICAL FEATURES. THERE IS, HOWEVER, LITTLE UNDERSTANDING OF THE STATIC AND DYNAMIC PERFORMANCE OF THE HYBRID CONNECTIONS THAT CAN BE USED TO DIRECTLY JOINT THESE MATERIALS TOGETHER, WHICH IS CRUCIAL FOR ITS STRUCTURAL DESIGN. IN THIS RESEARCH, THE STATIC AND PSEUDO-DYNAMIC RESPONSE OF CROSS-LAMINATED TIMBER (CLT) COMPOSITES COMBINED WITH REINFORCED CONCRETE (RC), HOLLOW STEEL PROFILES AND LAMINATED STRAND LUMBER (LSL) HAS BEEN INVESTIGATED. IN ADDITION, THE EFFECTS OF POSTTENSIONING STRESSES AS WELL AS DISTINCT TYPES OF CONNECTORS SUCH AS NAILS, SELF-TAPPING SCREWS AND STEEL SELF-TAPPING DOWELS HAS BEEN ACCOUNTED FOR. AFTER EXPERIMENTAL CHARACTERIZATION, NUMERICAL MODELLING FOR SIMULATING THE STATIC AND DYNAMIC BEHAVIOR FOR THESE HYBRID CONNECTIONS WAS ALSO INVESTIGATED. RESULTS INDICATE THAT SUCH MASSIVE TIMBER COMPOSITE CONNECTIONS BEHAVE REASONABLY SIMILAR TO CONVENTIONAL TIMBER CONNECTIONS, EXCEPT IN THAT INELASTIC DEFORMATIONS MAY INCREASE UP TO 200%. IN ADDITION, IT HAS BEEN FOUND THAT EXISTING HYSTERETIC MODELS LIKE THE MODIFIED STEWART HYSTERETIC MODEL (MSTEW) FIT FOR MODELLING PURPOSES EXCEPT THAT VERY ASYMMETRIC HYSTERETIC BEHAVIOR CAN BE FOUND FOR TIMBER-CONCRETE HYBRID CONNECTIONS. UNEXPECTEDLY, THE HYBRID CLT-CONCRETE CONNECTIONS WERE LESS RESISTANT AND STIFF UNDER POSTTENSIONING STRESS, WHICH MAY BE EXPLAINED DUE TO PREMATURE SHEAR FAILURE OF THE CONCRETE AT THE SHEAR PLANE OF THE CONNECTIONS.