Experimental Study On Material Selection Of Glulam Beam String Structure With Regulative Prestress

As an important branch of modern wood structure, glulam timber structure has been widely used for the advantages of energy-saving and gifted with inferior materials in architecture field all over the world. With the development of wood structure and the improvement of people’s life, higher requirement to glulam timber structure has been put forward on the aspects of security, applicability and durability of architecture. Large numbers of experimental study and theoretical analysis on prestressed wood structure have been explored at home and abroad, while for prestressed glulam timber structure, the study is just at the early stage. In this paper, adjustably prestressed glulam timber string beams were put forward and relative experiments were carried out, which can provide reference for the application of prestressed technology in glulam timber structure.Aimed at the prestressed glulam timber structure, a new prestressing method was put forward, which named threaded screw transverse stretching method. The prestressing device of threaded screw transverse stretching method was easy to operate, portable equipment, the restriction of large equipments and production sites for prestressed member can be casted off.Compression tests were carried out on102prism glulam timber test specimens, which were consist of wood material like SPF, poplar, northeast larch and eucalyptus, the modulus of elastic, compression strength parallel to grain and force-displacement curve were got with the ABAQUS finite element analysis software, the typical failure model of the test specimens were concluded, the influence of tree species sort, tree species combination, thickness of laminate and assemble pattern to the compression performance of glulam laminated timber were studied, which can be the basis of material selection of prestressed glulam timber structure. Experimental research shows that compression performance parallel to grain of poplar, northeast larch and eucalyptus were much better than that of SPF, which is a common import timber. Poplar and northeast larch were proved more suitable in prestressed glulam timber structure. There is a certain upward trend of the modulus of elastic and compression strength parallel to grain with the decrease of thickness of laminate, but the influence of thickness of laminate and assemble pattern to the compression performance are limited.