When we hear the word bridge it is not just only about connecting two ends, it also ensures the development and stability of the journey. There are more than hundreds and thousands of newly developed bridges in India which carry loads of many cars, heavy trucks & buses daily, so it becomes very important to give that the bridges should be joined properly and all the materials from which it is going to be made should be the best.
There are two methods through which bridges are joined: one is Bolting and another is Welding. Bolted joints can join two parts together but everything depends on the strength of the bolt and its thread. Welding is a more preferred way for bridge-building because the joints consist of fusing two different types of elements with extreme heat and pressure. There are several ways and methods to join two metal pieces of bridges together like if we talk about the processes shielded metal arc welding (SMAW), gas metal arc welding (GMAW/MIG), flux-cored arc welding (FCAW), gas tungsten arc welding (GTAW/TIG) and submerged arc welding (SAW) can be used. If we talk about the positions of welding like tee, lap, edge, butt, and corner positions are generally used for bridge building.
If we compare the cost of bolted joints and welded joints we come to know that the bolted joints process is cheaper than the welding process because the manufacturing of the bolts are cheaper and in the welding process, it cost of filler material or consumables may vary according to the type of metal they need to work upon. But if we compare them based on performance, welded joints are the best option because it provides more strength and we cannot take the risks when we talk about the lives and loads which are going to travel on the bridges.
While talking about the joint flexibility, the welding process gives more flexibility because two metal pieces can be fabricated together with filler metal which gives more strength as compared to the bolt joints where the level of flexibility is also good but due to limited applications, it restricts to give extra safety to the bridge.