Rubble Stone Masonry Buildings with Cement Mortar: Base Shear Seismic Demand Comparison for Selected Countries Worldwide

Full base shear seismic demand analyses with calculated examples for heavy stone masonry buildings are not present in the literature. To address this shortcoming, analyses and calculations are performed on nominally reinforced rubble stone masonry house and school designs, as typically built in Nepal. The seismic codes are literally applied for countries where the technique is still allowed (Nepal, India, China, Tajikistan, Iran, Croatia), or should be reintroduced based on current practices (Pakistan, Afghanistan, Turkey). First, this paper compares the base shear formulas and the inertia forces distributions of these codes, as well as material densities, seismic weights, seismic zoning, natural periods of vibration, response spectra, importance factors and seismic load combinations. Large differences between approaches and coefficients are observed. Then, by following Equivalent Lateral Force-principles for Ultimate Limit State verifications (10%PE50y), the base shear and story shears are calculated for a design peak ground acceleration of 0.20 g, as well as the effects of critical load combinations on the forces and moments acting on the lateral-resisting elements. It is concluded that Pakistan has the most tolerant code, Nepal represents an average value, whereas India and China are most conservative toward the case study buildings. Overall, it is observed that heavy-masonry-light-floor systems with negligible diaphragm action behave different under seismic motion than most other building typologies. Given the observations in this paper, the applicability of conventional ELF, S-ELF and S-Modal methods for heavy masonry buildings is questionable. The codes however do not introduce modified approaches that address these differences. Possible implications of the exclusion of plinth masonry and large portions of seismic weight need further assessment and validation, for which different (possibly more sophisticated) concepts must be considered, such as the equivalent frame method or distributed mass system. Since Nepal allows stone masonry in areas with higher seismic hazard levels >0.40 g (opposed to India <0.12 and China <0.15 g), their code is taken as the reference and starting point for follow-up research, which aims to verify the seismic demand by performing seismic capacity checks of the masonry piers and spandrels. The paper ends with an appeal for global collaboration under the research project SMARTnet.

文献中没有针对重型石砌体建筑的全基底剪力地震需求分析及计算实例。为弥补这一不足，对尼泊尔常见的名义上配筋的毛石砌体房屋和学校设计进行了分析和计算。地震规范在该技术仍然允许的国家（尼泊尔、印度、中国、塔吉克斯坦、伊朗、克罗地亚）得到了严格应用，或者基于当前实践应该重新引入（巴基斯坦、阿富汗、土耳其）。首先，本文比较了这些规范的基底剪力公式和惯性力分布，以及材料密度、地震重量、地震分区、自振周期、反应谱、重要性系数和地震荷载组合。观察到方法和系数之间存在很大差异。然后，遵循极限状态验证的等效侧向力原理（10%PE50y），针对设计峰值地面加速度为0.20g计算基底剪力和楼层剪力，以及临界荷载组合对作用于抗侧力构件上的力和力矩的影响。结论是巴基斯坦的规范最为宽松，尼泊尔处于中间水平，而印度和中国对于案例研究建筑最为保守。总体而言，观察到隔板作用可忽略的重型砌体 - 轻型楼板系统在地震作用下的行为与大多数其他建筑类型不同。鉴于本文的观察结果，常规等效侧向力（ELF）、简化等效侧向力（S - ELF）和简化模态（S - Modal）方法对重型砌体建筑的适用性值得怀疑。然而，规范并没有引入针对这些差异的改进方法。排除勒脚砌体和大部分地震重量可能产生的影响需要进一步评估和验证，为此必须考虑不同的（可能更复杂的）概念，例如等效框架法或分布质量系统。由于尼泊尔允许在地震危险水平>0.40g的地区使用石砌体（印度<0.12g，中国<0.15g），其规范被作为后续研究的参考和起点，后续研究旨在通过对砌体墩和拱肩进行抗震能力检查来验证地震需求。本文最后呼吁在SMARTnet研究项目下进行全球合作。