Earthquake-resistant performance investigation for rural buildings in Zhongxiang area, China

We carried out a census of the rural residential buildings of Zhongxiang area＇ s 17 towns. Next, we conducted a sample survey in four townships： Huji, Shipai, Zhangji, and Jiuli. According to the census and sample survey data of the rural residence buildings, we evaluated the quality and earthquake-resistant performance of the rural buildings for the various local rural residential structural types. The results showed that there are four main factors affecting the seismic performance of the local rural residences ： （ 1 ） Foundations are not made appropriately （ such as by compaction or some other fill） but are built directly in the farming soil. （2） Seismic measures are not completely implemented. Structure construction measures are not in place at the junction of the vertical and horizontal wall. The vertical wall joints are not the result of the same masonry techniques as the horizontal joints. There are no lintels above the door and window openings, or if there are any, the length of the lintels is less than 240 mm. （3） The brick masonry wall has low strength. The greatest housing wall mortar strength is between M0. 4 - 1.5, much lower than the strength of the brick. （4） The building material and construction quality are poor. The quality of the mortar masonry wall is poor. The cracks between the bricks are uneven, even in the seams.

Prediction of Nonlinear Cyclic Behaviors of Shear Wall Composed of Acacia mangium Framing and Fiber Cement Board Sheathing

The alternative types of composite structure made of wood and cement based building materials needs to meet with the high demand for earthquake-resistant houses in Indonesia. In order to understand the mechanism of earthquake resisting performance of shear wall, it is necessary to investigate not only elastic behavior of shear walls but also non-linear one. In this study, series of full-scale experiments on timber frame shear walls composed of Akasia wood (Acacia mangium) sheathed by Fiber Cement Board (FCB) were carried out. For predicting skeleton curve, a series of theoretical equations was derived, which cannot only solve arbitrary nail pattern shear wall but also nonlinear behavior after yielding. Further, for describing hysteresis loops of shear walls, so-called Normalized Cyclic Loop (NCL) model was adopted. By combining two theoretical approaches, weintended to predict whole cyclic shear wall behaviors tested. Good agreements were obtained from comparison between experiment and prediction. The information obtain by this study will be useful for practical engineers or structural designers to design the high performance earthquake resisting timber houses.

Seismic Performance of Dry-Friction Devices in Shear-Frame Buildings

In recent years the application of friction-based passive energy dissipation devices have been proven very effective in reducing structural response to earthquake excitations and also implemented for a large number of buildings. Their design heavily relies on numerical simulations to model the influence of the energy dissipation devices. The modeling of friction forces must be accurate for realistic simulation of the influence of these devices. In state-of-the-practice, the hysteretic behavior of friction devices has been typically modeled with Coulomb friction having a constant coefficient of friction. However, the basic laws for typical sliding materials and experimental investigations show non-linear relationship between friction and sliding velocity, which includes stiction and Stribeck effect. The influence of stiction and Stribeck effect may be significant and can not be ignored in simulating the dynamic responses of structures with friction-based energy dissipation devices. In this paper the optimal performance of dry friction device in shear-frame buildings when subjected to earthquake ground motions has been investigated. The focus of this paper is on the optimal minimization of response of the shear-frame building. Since buildings with friction devices behave in a highly nonlinear manner, nonlinear response-history analysis considering comprehensive sliding friction models has been carried out. The performance has also been evaluated using the various response measures： the maximum absolute acceleration, the maximum base shear, and the maximum inter-story drift. Different performance indices have been used to quantify the influence of the device properties.

Study on Impact of Embodied Energy and CO2 Emissions for Prolongation of Building Life Time： Case Study in Japan

In this study, we looked at a method quantifying EEC （embodied energy and CO2） and the effect when we prolonged the building life time particularly through the durable improvement of the structure. Increasing the covering thickness of concrete for reinforcing bars and the earthquake-resistant strength are methods to increase the durability of the structure. The calculation method to obtain the quantity of concrete and reinforcing bars is provided. The EEC increase is evaluated from the 2005 input-output table in Japan. These results show that EE （embodied energy） in the construction phase is increased by 11% to 20% and EC （embodied CO2） 17% to 32%. However, annual EE is reduced 66% to 72% and EC 70% to 79%,

Dynamic and Static Behaviors of Shear Wall with Openings Composed of LVL and Fiber Cement Board Sheathing

The shear wall with and without openings that served as a structural element or/and partition wall was utilized in a low-cost housing for the low-income people in Indonesia. The houses,however,should be withstoodfrom earthquake inertial force, so there must be no casualties when disaster struck. The alternative types of composite structure made of wood and cement based building materials needed to meet with the high demand for earthquake-resistant houses in Indonesia. In order to understand the mechanism of earthquake resisting performance of shear wall, we needs to investigate behavior of shear wallsnot only for cyclic static but alsofor dynamic loading. In this study, theseries of full-scale experiment on timber frame shear walls with and without openings,compose of Laminated Veneer Lumber (LVL) engineered wood (Paraserianthes Falcatariaand Hevea Brasiliensis) and sheathed by Fiber Cement Board (FCB), was carried out.By analyzing testing result using theoretical approaches, we intended to predict static initial stiffness and yielding strength as well as basic dynamic properties shear walls. For static behavior, good agreements were obtain from comparison between experiment and theoretical prediction based on mechanical model. While, for dynamic behavior, agreement was not sufficient due tothe effect of bending and rocking of actual test specimens. The information obtain by this study will be useful for practical engineers or structural designers to design the high performance earthquake resisting timber houses with a low construction cost.

Illustrations of verification for seismic properties of masonry structures in primary and secondary school buildings

After Wenchuan earthquake,Code for verification of Seismic Protection of Building is revised and the seismic verification for the buildings of primary and secondary schools is upgraded from Class C to Class B. With this background,nearly one hundred buildings of primary and secondary schools in Jilin Province have been reevaluated by the earthquake-resistant standards and a set of simplified earthquake-resistant evaluation methods based on relevant technical standards and regulations were summarized and presented here. These methods can serve as an important reference for future earthquake-resistant evaluation for primary and secondary school buildings as well as a convenient guide for the relevant construction and modification works.

Research on seismic performance and design method of combined steel lead energy dissipation structure(Ⅰ)

A new combined steel lead damper (NCSLD) was presented. Construction and working mechanism of NCSLD were introduced,pseudo-static tests of the small size dampers which would be used in the subsequent shaking table tests were carried out for the study of mechanical properties of NCSLD using electro-hydraulic servo press-shear machine. Processing technology of the damper was improved. Shaking table tests under two-dimensional excitation on structural aseismic control of a one-story structure model were carried out using the small size NCSLD; parameters of the structure and shaking table were also introduced. Results indicate that process improvement is beneficial to the implementation of working mechanism of the damper,NCSLD has full hysteresis loop which takes on bilinearity,NCSLD has obvious energy dissipation effect and it can control structural seismic response effectively.