格雷格·哈夫（Greg Havel）的文章和照片
Several结构崩溃不涉及结构的事件火have been in the news recently. The most recent of these occurred inPhiladelphia, Pennsylvania，2013年6月5日，在一栋被拆除的建筑物上。四层楼的砖墙的一部分倒在隔壁的单层旧货店上。在此事件中，有6人被杀，14人受伤。当墙壁倒在屋顶上时，这些伤亡大多数都在旧货店内。一位目击者说，当墙壁开始摇摆时，一架起重机从建筑物的前部卸下了一束横梁collapsed到相邻的一层建筑。
We must remember that a building is a结构系统。Each component is connected to other components and serves multiple functions.
- 负载墙壁和柱将地板和屋顶分开，并将这些负载带到基础
- 地板和屋顶梁和大梁支撑着建筑物的地板和屋顶，并支撑墙壁对抗横向力
- Floor and roof decks provide the working surface at each level and, after connection to the joists and girders, provide additional bracing to these assemblies
- 隔板（非负载）墙壁分开建筑物的内部区域，并为外墙提供侧向支撑
- The building envelope (exterior walls and roof) keeps out the weather and preserves the interior of the structure from moisture and temperature extremes
- Connections join structural components and assist in transferring loads from one component to another.
照片1显示了不可燃烧的（II）正在建造的建筑物。The steel bar joists are being set between the load-bearing masonry walls in the foreground and in the middle. The top course of concrete masonry units on the middle wall is a “bond beam”– blocks with a U-shaped cross section. This U-shaped cavity forms a continuous channel in the top of the wall which is filled with reinforcing steel and concrete grout to stiffen the top of the wall and provide for the installation of “setting plates” (at the arrows). These in turn are embedded in the concrete grout and the bar joists are welded to them. The top course on the wall in the foreground will also be a bond beam, after the installation of the reinforcing steel and concrete grout. The bar joists will connect and stabilize the walls; and the steel roof deck that will be welded to the bar joists will provide resistance to lateral and other forces that may be applied to the completed building.
照片2显示了拆除下的单层建筑物。车库门上的lintel已被拆除，还取下了支撑屋顶托梁末端的光束。这些屋顶托梁正在下垂，在墙壁上施加了内向的力，试图将它们拉进去。这类似于发生的事情Philadelphia，除了在费城外，被拆除的光束破坏了一堵四层楼的墙，摇摆着，collapsedoutward. In Photo 2, the collapse zone was marked, cleared of all by-standers, and spotters were assigned to keep spectators away.
当建筑物被拆除时，其结构系统被拆除时被破坏。如果没有系统地完成此操作，并且在适当的时间和时间内没有断开连接，则建筑物的其余部分将不稳定，并且很可能会做意外的事情。如果墙壁的截面变得不受支持，或者地板或屋顶的部分变成悬臂，则必须在小部分中将其去除，以便可以控制掉落的碎屑方向。
结构组件之间的共同连接包括砂浆，加固钢，指甲，螺钉，粘合剂，铆钉，螺栓，焊缝，螺栓，毛刺板和托梁吊架。其中一些连接比其他连接更强，拆除应在较弱的连接处拆分组件，以避免以不受控制的方式无意间拉下大部分结构。
Emergency services personnel who are dispatched to a structural collapse during building demolition are responding to the ultimate “needless call.” Had the demolition contractor established a collapse zone and performed the work according to accepted procedures, the collapse during demolition would not require search and rescue with all of the hazards to responders to a collapse during a fire, except for heat, smoke, and flooded cellars. Furthermore, responders would not be required to perform search and rescue on, in, or next to an unstable structure.
Construction workers and building contractors are educated, serve apprenticeships in their trades, and are licensed to perform their work. Firefighters are educated, trained, and certified before working as firefighters and participate in a continuing education program. Demolition workers and contractors should also be required to be educated, serve apprenticeships, and be licensed by a state or municipality before performing this type of work.
将本文作为PDF下载这里。
格雷戈里·哈维尔（Gregory Havel）is a member of the Town of Burlington (WI)Fire Department; retired deputy chief andtraining officer; and a 30-year veteran of thefire service。他是威斯康星州认证的fire instructorII, fire officer II, and fire inspector; an adjunct讲师在fire serviceprograms at GatewayTechnical大学;和安全Scherrer Construction Co.，Inc。Havel拥有圣诺伯特学院的学士学位；在设施管理和建筑建设方面拥有30多年的经验；并已在FDIC介绍课程。
MORE CONSTRUCTION CONCERNS
