ABSTRACT

Experimental and numerical studies performed on traditional timber-frame masonry buildings have confirmed excellent deformability of timber structure; however, observations from dynamic shake table tests and earthquakes have revealed the potential hazard of stone falls poses a risk for occupants to get injured. This research presents a seismic performance evaluation study carried out on a traditional two-story Dhajji-Dewari structure having reduced diagonal braces for economizing construction. Moreover, one in-plane wall and one out-of-plane wall were retrofitted with typical steel wire mesh to control dislodging and fall of infill stones. Shake table tests were performed on a representative 1:3 reduced scale test model. The testing was performed using natural acceleration time history with multi-level excitations. The structure damage mechanism was observed with increasing intensity of base motion. The fundamental dynamic properties like frequency, damping, and acceleration amplification factors were obtained. The structure lateral force-deformation capacity curve was derived and bi-linearized to compute the structure ductility, overstrength, response modification factors (approximated to 3.0), and to develop structural global performance levels (i.e. roof drift limits, the corresponding base shear coefficients, and the wall damage states). A simplified procedure was also presented for the global seismic performance assessment of the Dhajji-Dewari structure in various seismic zones. The overall behavior of the model was observed to be good; however, the Immediate Occupancy and Life Safety limit states were primarily governed by the falling of infill rubbles from walls without steel wire mesh. The proposed steel wire mesh negligibly contributes to the lateral stiffness and strength of the structure and primarily prevented the dislodging and fall of stones. The proposed response modification factor can be used for the seismic analysis of structures using an elastic model to compute design forces for timber members and connection fasteners.

摘要

对传统木结构砖石建筑进行的实验和数值研究证实了木结构的优良变形能力；然而，动态振动台测试和地震的观察结果表明，石头坠落的潜在危险会给居住者带来受伤的风险。本研究介绍了对传统的两层 Dhajji-Dewari 结构进行的抗震性能评估研究，该结构具有减少的斜撑以节省施工。此外，在一面内墙和一面外墙上加装了典型的钢丝网，以控制填充石的脱落和脱落。振动台测试是在具有代表性的 1:3 缩小比例测试模型上进行的。使用具有多级激励的自然加速度时程进行测试。随着基础运动强度的增加，观察到结构损伤机制。获得了频率、阻尼和加速度放大因子等基本动态特性。导出结构侧向力-变形能力曲线并对其进行双线性化，以计算结构延性、超强度、响应修正因子（近似为 3.0），并制定结构整体性能水平（即屋顶漂移限制、相应的基础剪切系数、和墙壁损坏状态）。还提出了一个简化程序，用于对不同地震带中的 Dhajji-Dewari 结构进行全球抗震性能评估。观察到模型的整体行为良好；然而，立即入住和生命安全限制状态主要由填充瓦砾从没有钢丝网的墙壁上掉落来控制。所提议的钢丝网对结构的横向刚度和强度的贡献微乎其微，主要防止了石头的移位和掉落。建议的响应修正因子可用于结构的地震分析，使用弹性模型计算木构件和连接紧固件的设计力。