FINITE ELEMENT ANALYSIS OF THE STRUCTURAL PERFORMANCES OF COMPOSITE TIMBER-STEEL-TIMBER BEAM USING STEEL BOLT CONNECTORS UNDER FIRE CONDITIONS

Abstract

In a construction of structures, timbers can be applicable in combination with concrete or steel materials to form composite structure systems. A composite structure system combines different material properties to achieve the requirement of design such as fire and structural safety. In this thesis, timber-steel-timber composite beam was considered. This composite timber-steel-timber beam consists of Glulam timber, I-section steel and steel bolt connecters. The performance of these beams is evaluated under normal weather condition and standard fire condition using a modeling of finite element. Based on analysis method of sequentially coupled thermal-stress analysis, the numerical simulation for the performances in temperature and displacement field were performed by using ABQUS, software of finite element for timber-steel-timber composite beams with embedded I section steel element within Glulam timber connected by ethane epoxy adhesive and steel bolts under ISO 834 standard fire for thirty minutes. The major parameters in the study include fire exposure condition; load and composite beam configuration were considered to study their influence on the behavior of the composite beam. The obtained results from this study indicated that the steel bolt connectors has adversarial effect on distribution of temperature in I-section embedded steel at a great extent, leads to the fast heating and loss of the strength and the final failure of composite timber-steel-timber beam structure, but under normal weather condition the steel bolt connectors have advantages on structural integrity by connecting the timber layers and I section steel and load transfer between the materials in composite beam structure. By applying the pressure load on top of timber-steel-timber composite beam, the composite beam with reduced steel bolt spacing have greater resistance of loading by 1.49% under normal weather condition and 0.07% than standard composite beam and under 30 minutes fire incidents. For the composite timber-steel-timber beam with reduced bolt spacing indicted that that the performance of structure has greater deformation by 4.52% than that of standard composite beam after 30 minutes fire.