Study On Seismic Behavior Of China’s Western Traditional Rammed Earth Resident Buildings*

China’s western region has vast land, multitudinous nationalities. The different style traditional resident buildings as an exotic flower in Chinese architectures are also an example of the unique and magnificent. As an important inhabitancy form, rammed earth dwellings have the advantages of using local materials, economical and applicable, good thermal property, convenient construction, regional style. And Rammed earth dwellings have been widely used in our country vast western rural regions. However, the seismic performance of rammed earth resident buildings is an insurmountable difficulty. This paper conduct research on the basis of the seismic performance of rammed earth resident buildings, the main contents are present as follow:The composition of traditional resident buildings and development process of settlement are concluded and analyzed. The open space in front of the yard steps is courtyard in our traditional buildings, and residential homes generally have a yard. The implication, function and composition form of yard, courtyard and residential homes are described in detail. The types of loading-bear walls in traditional building are described. The types, production process and characteristics of stone wall, wood wall, brick wall, soil wall and other walls are introduced in detail. The roof shapes and constitution of traditional dwellings are the richest and most attractive. And the development history, structural system and structural form of timber frame in traditional dwellings are described. The seismic constitution strategy of rammed earth dwellings is studied. The physical and mechanical properties of general wall soil are analyzed. The influence of different admixtures on the optimum moisture content of soil, shrinkage deformation properties, bond force and wall waterproof measures are analyzed. And the related indexes and construction method are proposed. several new types shear walls such as cast-in-site adobe plaster green wall, straw bricks building, weave fence raw soil wood structure wall are researched and the raw materials, structure compounds and construction method of these types walls are proposed. On the basis of western regional characteristics, the earthquake resistant constructional measures of traditional raw soil dwelling in Xinjiang, Yunnan and southern Shaanxi region are studied and analyzed, and the earthquake resistant constructional improvements measures of these walls are proposed.Taking Yunnan and Xinjiang Province as an example, rammed earth walls used widely and earthquakes occurred frequently. The seismic damages of buildings were investigated and analyzed. The problems in buildings and structures of rammed earth walls-timber frame houses are summarized. The failure modes and seismic damages levels are analyzed. Then, based on concept design, the earthquake resistant constructional measures and construction quality, the seismic behavior improvements measures of rammed earth walls-timber frame houses are proposed.Based on the experimental study on six rammed earth walls including pure-soil wall, lime-soil wall and grass-soil wall subjected to monotonic load and low-cyclic and reverse load, the failure process, failure modes, bearing capacity, deformation and ductility properties, stiffness property and hysteretic behavior are investigated. The test results indicate that rammed earth walls present shear failure under monotonic load and low-cyclic and reverse load. The load-displacement curves and skeleton curves variation of three types of walls are similar. The bearing capacity is similar, but the ductility factor of grass-soil wall is slightly lower. The ultimate stiffness of lime-soil wall is greater than the pure-soil wall and grass-soil wall. The Energy dissipation capacity of pure-soil wall is the best, the lime-soil wall take second place, and the grass-soil wall is the worst. The ultimate load under low-cyclic load is 81%~85% of ultimate load under monotonic load. The shearing capacity formula and seismic capacity of the rammed earth walls are obtained by using the formulas of masonry structure. The value calculated by the formula is close to the test value.Taking the rammed earth walls dwellings in southern Shaanxi region as prototype, two“U”type rammed earth walls specimens were designed and tested on the shaking table. One specimen is reinforcement model, another is not. The dynamic characteristics, acceleration response and displacement response were comparing researched, the failure mechanism and features of rammed earth walls were analyzed, and the reliability and feasibility of reinforcement measures were also verified. The test results indicate that rammed earth dwelling by reasonable seismic strengthening meet the requirements regulated by Chinese design codes.