a common way to construct steel truss and prestressed concrete cantilever spans is to counterbalance each cantilever arm with another cantilever arm projecting the opposite direction,forming a balanced cantilever. they attach to a solid foundation ,the counterbalancing arms are called anchor arms /thus,in a bridge built on two foundation piers,there are four cantilever arms ,two which span the obstacle,and two anchor arms which extend away from the obstacle,because of the need for more strength at the balanced cantilever's supports ,the bridge superstructure often takes the form of towers above the foundation piers .the commodore barry bridge is an example of this type of cantilever bridge一种常见的方法构造钢桁架和预应力混凝土悬臂跨度是每一个悬臂抗衡预测相反的方向臂悬臂，形成一个平衡的悬臂。

他们重视了坚实的基础，制约武器被称为锚武器/因此，在两个基础上建一座桥桥墩，有四个悬臂式武器，这两者之间跨越的障碍，和两个锚武器哪个延长距离的障碍，因为为更多的在平衡悬臂的支持力量的需要，桥梁上部结构往往表现为塔墩基础之上形成的准将巴里大桥是这种类型的例子悬臂桥steel truss cantilever support loads by tension of the upper members and compression of the lower ones .commonly ,the structure distributes teh tension via teh anchor arms to the outermost supports ,while the compression is carried to the foundation beneath teh central towers .many truss cantilever bridges use pinned joints and are therefore statically determinate with no members carrying mixed loads钢桁架悬臂由上层成员和下层的紧张压缩支持负载。

通常，结构分布通过锚武器的最外层的支持紧张，而压缩抬到下方的中央塔的基础。

桁架悬臂许多桥梁使用固定的关节，是静定，没有携带混合负载的成员，因此prestressed concrete balanced cantilever bridges are often built using segmental construction .some steel arch bridges are built using pure cantilever spans from each sides,with neither falsework below nor temporary supporting towers and cables above ,these are then joined with a pin,usually after forcing the union point apart ,and when jacks are removed and the bridge decking is added the bridge becomes a truss arch bridge .such unsupported construction is only possible where appropriate rock is available to support the tension in teh upper chord of the span during construction ,usually limiting this method to the spanning of narrow canyons预应力混凝土平衡悬臂桥梁往往建立使用段施工。

一些钢拱桥是使用各方面的纯悬臂跨度既无假工作下面也临时支撑塔和电缆上面，这些都是再加入了一根针，通常在迫使工会点外，当插孔删除，并添加桥梁甲板桥成为桁架拱桥，这种不支持的建设，才可能在适当情况下的岩石可用于支持在施工期间的跨度弦上的张力，通常限制这狭隘的峡谷跨越方法an arch bridge is a bridge with abutments at each end shaped as a curved arch .arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side .a viaduct may be made from a series of arches ,although other more economical structures are typically used today在拱桥桥台的桥梁，是一个在一个弧形拱状，每年年底。

拱桥通过转移到由部分在两边的桥台水平推力内敛的桥梁和其工作负载的重量。

高架桥可能从做系列拱门，虽然其他更经济的结构通常用于今天the corbel arch bridge is a masonry or stone bridge where each successively higher course cantilevers slightly more than the previous course .the steps of teh masonry may be trimmed to make the arch have a rounded shape .the corbel arch does not produce thrust ,or outward pressure at the bottom of the arch ,and is not considered a true arch ,it is more stable than a true arch because it does not have this thrust .the disadvantage is that this type of arch is not suitable for large spans在牛腿拱桥是砖石或石桥当然，每个先后高悬臂比以前的课程等等。

砌体的步骤可能被修剪，使拱有一个圆形的牛腿拱不产生推力，或向外压在拱底部，不被视为一个真正的牌坊，它比真正的拱稳定，因为它没有这种推力，其缺点是，这种弓型不适合大跨度in some loactions it is necessary to span a wide gap at a relatively high elevation ,such as when a canal or water supply must span a valley .rather than building extremely large arches ,or very tall supporting columns ,a series of arched structures are built one atop another ,with wider structure at the base .roman civil engineers developed teh design and constructed highly refined structures using only simple materials ,equipment ,and mathematics .this type is still used in canal viaducts and roadways as it has a pleasing shape .particularly when spanning water ,as the reflections of the arches form a visual impression of circles or ellipses在某些位置，必须跨越一个相对较高的海拔悬殊，比如，当一个或供水管必须跨越山谷。

而不是建立非常大的拱门，或非常高的支持柱，拱形结构的一系列建one之上另一个在该基地的结构矛盾，发达国家罗马土木工程师设计和建造高度精炼的结构只使用简单的材料，设备和数学。

这种类型采用的依然是运河高架桥和道路，因为它有一个可喜的形状，尤其当跨越水，作为拱门反射形成圆形或椭圆形的视觉印象this type of bridge comprises an arch where the deck is completely above the arch .the area between the arch and the deck is known as teh spandrel .if the spandrel is solid ,usually the case in a masonry or stone arch bridge ,it is called a closed-spandrel arch bridge .if the deck is supported by a number of vertical columns rising from the arch ,it is known as an open-spandrel arch bridge .the Alexander HamiltonBridge is an example of an open-spandrel arch bridge这种桥型拱其中包括在甲板上完全凌驾于拱的拱之间的甲板面积和拱肩是已知的，如果拱肩是固体，通常是在砖石或石拱桥的情况下，它被称为一个封闭拱肩拱桥，如果甲板是由从拱上升的垂直列数的支持，它被称为拱肩拱桥打开的亚历山大汉密尔顿大桥是一个开放式拱桥拱肩例子this type of bridge comprises an arch which supports the deck by means of suspension cables or tie bars .the Sydney Harbour Bridge is a through arch bridge which uses a truss type arch .these through arch bridges are in contrast to suspension bridges which use the catenary in tension to which the aforementioned cables or tie bars are attached and suspended这种桥型包括哪些拱支持的甲板悬挂电缆或拉杆手段。