Article and photos by Greg Havel
一些structural collapse一世ncidents that did not involve structurefires最近一直在新闻中。最近的这些发生在费城，宾夕法尼亚州, on June 5, 2013, at a building that was being demolished. Part of a four-story brick wall collapsed onto the single-story thrift store next door. Six were killed and 14 were injured in this incident. Most of these casualties were inside the thrift store when the wall collapsed onto its roof. One witness stated that a crane removed a beam from the front of the building when the wall began to sway and崩溃了onto the adjacent one-story building.
我们必须记住建筑物是一个structural system。每个组件都连接到其他组件并服务于多个功能。
- Load-bearing walls and columns separate the floors and roof from each other and carry these loads to the foundation
- Floor and roof beams and girders support the floors and roof of the building, as well as brace the walls against lateral forces
- 地板和屋顶甲板在每个级别提供工作面，并在与托梁和梁连接后，为这些组件提供额外的支撑
- Partition (nonload-bearing) walls separate interior areas of the building, and provide lateral bracing for the exterior walls
- 建筑信封（外墙和屋顶）远离天气，并保留水分和温度极端结构的内部
- 连接连接结构组件并帮助将负载从一个组件传输到另一个组件。
Photo 1 shows a non-combustible (II型）建设建筑。钢筋托梁在前景和中间的承载砌体墙壁之间设置。中间壁上的混凝土砌体单元的顶级过程是“债券梁” - 带U形横截面的块。该U形腔在壁的顶部形成连续通道，其填充有加强钢和混凝土灌浆，以使壁的顶部硬化并提供“设定板”（在箭头处的安装）。这些反过来嵌入混凝土灌浆中，并且杆托梁焊接到它们。前景墙上的顶级路线也将是粘合梁，安装加强钢和混凝土灌浆后。杆梁将连接和稳定墙壁;并且将焊接到杆托梁的钢屋顶甲板将为可以应用于完整的建筑物的横向和其他力提供抵抗力。
图2显示了一个单层建筑demoli之下tion. The lintel over the garage door has been removed, also removing the beam that supported the ends of the roof joists. These roof joists are sagging, exerting an inward force on the walls, attempting to pull them in. This is similar to what happened in费城, except that in Philadelphia, the beam that was removed destabilized a four-story wall that swayed and崩溃了向外。在Photo 2中，崩溃区域被标记，清除了所有旁路，并分配了Spotters以防止观众。
When a building is demolished, its structural system is being destroyed as it is taken down. If this is not done systematically, and if connections are not broken at the proper place and time, the remaining parts of the building will be unstable and will be likely to do unexpected things. If sections of walls become unsupported or if sections of floors or roofs become cantilevers, these must be removed in small sections so that the direction of falling debris can be controlled.
Common connections between structural components include mortar, reinforcing steel, nails, screws, adhesives, rivets, bolts, welds, gusset plates, and joist hangers. Some of these connections are stronger than others, and the demolition should break components apart at the weaker connections to avoid inadvertently pulling down a large part of the structure in an uncontrolled manner.
在建筑拆迁期间派遣到结构崩溃的紧急服务人员正在响应终极“不必要的电话”。拆迁承包商是否建立了崩溃区并根据已接受的程序进行工作，拆迁期间的崩溃将不需要在火灾期间对响应者的所有危害进行搜索和拯救，除了热量，烟雾和洪水的酒窖。。此外，不需要响应者在不稳定的结构中执行搜索和拯救或禁止。
建筑工人和建筑承包商受过教育，在交易中提供学徒，并获得许可以执行他们的工作。在作为消防队员工作之前，消防员受过教育，培训和认证，并参与继续教育计划。拆迁工人和承包商也应被接受教育，服务学徒，并在执行此类工作之前由州或市政府许可。
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Gregory Havel一世伯灵顿镇（WI）的一名成员消防部门;退休的副主任和培训人员;和30年的退伍军人消防。He is a Wisconsin-certified消防教练II，消防官II和消防督察;辅助一世nstructor一世n消防网关节目技术的College; andsafetydirector for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College; has more than 30 years of experience in facilities management and building construction; and has presented classes at FDIC.
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