经过格雷戈里·哈维尔（Gregory Havel）
已经多次指出，承载结构支撑的连接是建筑物中的弱点。如果结构系统旧或维护不佳，则尤其如此。这些连接尤其容易受到火灾的失败，由建筑物内容物或由风，大雪或地震等自然力量压力。
照片1显示了在1880年左右建造的柱和框架（柱和梁）谷仓中的三个artise和tenon关节。该关节被称为“树指甲”或“ Trunnels”的木销钉固定。弯腰和肾小管是由手工工具制成的，并且非常适合。随着木材的老化和干燥，自然收缩，随着时间的推移，风的压力和试图使结构摇摆的风压力使关节松动。在这张照片中，从暴露到水分的腐烂似乎不是问题。照片的顶部是两个较小的弯腰和齿轮关节，带有trunnels，将Girts连接到圆柱。戴着垂直壁板的指甲也可见。当壁板板变得风化和腐烂时，他们仍然保护了谷仓框架免受天气的影响。
照片2显示了1895年左右建造的重型教堂下爬行空间的景色。在照片中，砌体码头支撑着两条梁的末端，这些横梁将撞到并支撑地板托梁和舌头和槽木板地板。这些被认为是“重力连接”，因为除重力和摩擦外，没有其他连接将光束固定在码头或托梁上。在码头的顶部，两条梁的束缚末端由一对“狗铁”保持在对齐中。这些锻铁或钢的扁平条带有90度弯曲，在梁上弯曲。狗铁被滞后螺钉固定在梁中。狗铁通常成对安装，横梁对接接头的每个相对侧面一个。
图3显示了梁和柱磨机若干uction (heavy timber, Type IV) building constructed in the early 1840s in southeastern Wisconsin. Although this was 40 years before the National Board of Fire Underwriters published their specification for mill construction, it incorporated several of the features that would become code requirements. The column has chamfered corners to eliminate the square corners that are more easily ignited due to their relatively thin cross-section. The wooden girder is carried by a hand-hewn wooden saddle on top of the column. The joint between the column and the saddle has a piece of plank nailed to it, to preserve the integrity of this joint as long as possible if there is a fire. The ceiling of the room is the underside of the tongue-and-groove plank floor above, supported by wood joists; eliminating concealed spaces.
照片4显示了在承载砌体壁上的梁的末端，该砌体是由砖柯贝尔上的铁板携带的。这增加了砌体上梁的轴承区域，同时允许其末端放火，以便在发生火灾的情况下可以释放而不会倾斜墙壁。
Photo 5 shows a column and beam in a mill construction building constructed in the early 1880s, following the National Board of Fire Underwriters specification for this type of building. The column has chamfered corners. The wooden beam is carried by a cast-iron saddle on top of the column, which protects the joint between the column and beam, and distributes the load. The joint between the ends of butted beams is covered with a piece of plank. The automatic fire sprinkler pipe in the background is original equipment required by the NBFU specification, although the pipe hangers have been replaced, and the sprinkler heads changed periodically according to the schedule in National Fire Protection Association Standard 13,Standard for the Installation of Sprinkler Systems。
仅年龄就不会谴责建筑物。所有这些建筑物都得到了良好的维护和保护，因此在120 - 170年后，内部的木材框架仍处于良好状态。目前，谷仓的状态尚不确定，决策过程中的天气接触不会改善其状况。教会仍在用作教堂。这两栋磨坊建筑物今天仍在使用，1840年代用于零售的建筑以及1880年代的制造家用电器建筑。
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格雷戈里·哈维尔（Gregory Havel）is a member of the Town of Burlington (WI) Fire Department; retired deputy chief and training officer; and a 35-year veteran of the fire service. He is a Wisconsin-certified fire instructor II, fire officer II, and fire inspector; an adjunct instructor in fire service programs at Gateway Technical College; and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College; has more than 35 years of experience in facilities management and building construction; and has presented classes at FDIC.
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