土木工程外文翻译-建筑结构(编辑修改稿)

土木工程外文翻译-建筑结构(编辑修改稿)内容摘要：

l plot of a damped cyclic motion. Although the equation is technically sufficient to describe the phenomenon, the graph illustrates many aspects of the relationship. such as the rate of decay of the displacement. the interval of the vibration. the specific position at some specific elapsed time. and so on.. METHODS OF INVESTIGATION AND DESIGN Traditional structural design centered on the working stress method. a method now referred to as stress design or allowable stress design (ASD). This method. which relies on the classic theories of elastic behavior, measures a design39。 s safety against two limits: an acceptable maximum stress (called allowable working stress) and a tolerable extent of deformation (deflection. stretch. erc.). These limits refer to a structure39。 s response to service loadsthat is. the loads caused by normal usage conditions. The strength me/hod, meanwhile, measures a design39。 s adequacy against its absolute load limitthat is. when the structure must fail. To convincingly establish stress. strain. and failure limits, tests were performed extensively in the field (on real structures) and laboratories (on specimen prototypes. or models). Note: Realworld structural failures are studied both for research sake and to establish liability. In essence. the working stress method consists of designing a structure to work at some established percentage of its total capacity. The strength method consists of designing a structure tofail. but at a load condition well beyond what it should experience. Clearly the stress and strength methods arc different. but the difference is mostly procedural. The Stress Method (ASD) The stress method is as follows: 1. Visualize and quantify the service (working) load conditions as intelligently as possible. You can make adjustments by determining statistically likely load binations ( , dead load plus live load plus wind load). considering load duration. and so on. 2. Establish standard stress. stability, and deformation limits for the various structural responsesin tension. bending, shear, buckling. deflection, and so on. 3. Evaluate the structure39。 s response. An advantage of working with the stress method is that you focus on the usage condition (real or anticipated). The principal disadvantage es from your forced detachment from real failure conditionsmost structures develop much different forms of stress。