Overview of the activity in this learning activity, we will use a specially developed software package called the west point bridge designer to design a truss bridge. If you are interested in learning more about trusses and truss design, check out truss fun, second edition from amazon. Patented in 1820, the truss was constructed of a closely spaced array of intersecting diagonal members forming a web between the parallel chords. Design and evaluation of steel bridges for fatigue and fracture reference manual. Click reactions or axial force to display your results in a nice, clean and easytointerpret graph for your truss design. Users can also control settings such as units, display settings of truss members etc. There are more bridges in pennsylvania using the burr truss design than all other truss designs. Model truss bridge design william berry, kaleb dyer, dustin schultz and dr. Overview design it is the essence of engineering topics of discussion. The connected elements typically straight may be stressed from tension, compression, or sometimes both in response to dynamic loads. We were given specific specifications that we needed to follow, or else or. Consequently, the bridge design manual and traffic detail sheets have been modified as follows.
Edsgn100 truss bridge design final design report executive summary we were approached by a company to design a bridge that was strong, aesthetically pleasing, and economically efficient. To design a light weight structure with maximum strength, durability and safety factor. Now the bridge is thickest over the pier, with less material in midspan. A guide to bridge design and construction tells you everything you need to know about bridge construction, repair, design, and maintenance. Add aesthetics to your bridge structure with the thru truss from u. It also shares with you the interesting stories related with the greatest, tallest, and longest bridges of the world. Crane girder design 31 horizontal truss attached to the top flange of the girder and a back up girder to form a truss to stabilize. The burr arch truss, as the design became known, used two long arches, resting on the abutments on either end, which typically sandwiched a multiple kingpost structure. The truss bridge was designed to determine member sizes, extract a bill of materials and apply live project cost rates for a range of geometry. The prefabricated steel truss pedestrian bridge industry is mature with thousands of successful structures nationwide. Thus it appears as if there could not be any clear judgment, as far as.
Our bridge design is a hybrid of a camelback and k truss design, we thought that the curvature gave the design a better appeal to people and overall created a more aesthetic bridge. The foot over bridge spans for a total length of 28m over 3 tracks. Bollman truss railroad bridge in savage, maryland features revolutionary allmetal design. The bureau of bridge design is updating the bridge design manual. In the through type, the carriage way is supported at the bottom chord of trusses. Simple truss solver, as the name suggests, is a free truss design calculator software.
Users can also control settings such as units, display settings. In the process of designing a truss bridge, along with application of newtons laws of motion, certain assumptions are taken into consideration. Trusses are popular for bridge building because they use a relatively. A truss bridge is a bridge whose loadbearing superstructure is composed of a truss, a structure of connected elements usually forming triangular units. You can modify these existing projects or start with a new one. Three names stand out as true pioneers in these early truss bridges. Ce 331, fall 2000 truss design example 1 8 design a typical steel truss girder to support the roof of the office building shown below. New bridge design information is continually developing. To analyse and design a foot over bridge at a railway station in a metropolitan city. With its picturesque design, the wooden truss bridge has a near universal appeal. With a very basic and common bridge appearance, we felt the aesthetics would be familiar to a common person.
Truss design model bridge learning kits garretts bridges. W e have identified six general trail bridge types. Introduction to the design of wood trusses by derek l. In fact, peoples tastes can be very different, especially in aesthetics. The results showed an average reduction in cost for the truss bridge of approximately 3% by using the optimised geometry. Truss facts book an introduction to the history design and mechanics of prefabricated timber roof trusses. The 4 key roles in the design construction process. It lets you draw a truss structure and calculate truss problem.
How does construction quality affect the end performance of a structure. Dec 14, 2017 three names stand out as true pioneers in these early truss bridges. Truss bridge, bridge with its loadbearing structures composed of a series of wooden or metal triangles, known as trusses. Cablestayed bridge suspension bridge truss bridge bridge type posters arch bridges beam bridges cablestayed bridges suspension bridges truss bridges curriculum page number the bridge basics program kithas been produced in partnership with the construction industry round table cirt. This manual is intended to provide general guidance, and not solutions that are specific to any project. A truss is a series of individual members, acting in tension or. It is a historically significant bridge due to its unusual cantilever truss design and is listed. To make use of a simple and effective design methodology and construction. The basic types of truss bridges shown in this article have simple designs which could be easily analyzed by. Design of a truss bridge for low cost using structural.
We will measure some of the angles in our truss both before and after a load is appliedin order to calculate the amount of deflection. Trusses have a very high strengthtoweight ratio, which allows them to span long distances. The bridge is observed to be thinnest at the piers, and thickest between them. Teacher tips objective students will design and build a truss bridge to span a 61 cm 24 in open space. Design of industrial truss university of asia pacific.
We discuss about the various aspects related to bridge construction, which include seismic retrofitting of bridges, planning of bridge. You can do a web search for truss design and see many more examples. Background truss gusset plates and connections of truss members to the gusset plates are ordinarily stronger than the truss members to which they are connected. Depending upon the site conditions and the span length of the bridge, the truss may be either through type or deck type.
Key terms to successfully complete this learning activity, you must understand the following key terms and concepts from previous learning activities. Design considerations for pedestrian truss bridge structures. Aashto lrfd bridge design specifications specific to new mexico bridge design practice so that uniformity in bridge design procedures will be attained. Bollman truss very rare truss type that survives today in the only bridge of its design left standing. The site chosen for the design of foot over bridge is park railway station located in chennai district, tamil nadu. A presentation on truss bridges and its types by azaz ahmed cib09015 contents about truss and truss bridges truss configurations types of truss bridges choice of truss type and configuration design algorithm related advantages and disadvantages. Design data the various parameters considered in the design of foot over bridge are as follows. Bridge structures, the unique double bottom chord tension member design eliminates the possibility for the collection of water and debris, which will lead to the accelerated deterioration of the steel thereby reducing the useful life of the structure. The pieces of the truss are arranged to follow the 043. During this process, certain design decisions are being issued for immediate implementation. Almost everything has an internal structure and can be thought of as a structure.
Shen liu west kentucky community and technical college fig. We will use the software to create a structural model, then run a simulated load test to evaluate the design. Fill in the fields as appropriate under the description tab. Abstract the purpose of this example is to illustrate the use of the aashto lrfd bridge design for the design of a continuous two span steel igirder bridge.
Cablestayed bridges have one or more towers, each of which anchors a set of. It is particularly useful as a steel bridge truss design software or roof truss calculator. For many years, travelogues and historians alike have documented them and promoted their preservation, more than any other bridge type. Planar truss, on the other hand has a 2dimensional design.
These different types of bridges, as well as different material types, have differing span limitations. A more economical truss is designed like a continuous beam, which removes the joint at the pier, and allows the truss to bend over the pier. Truss bridges bowstring or parallel chord pony truss bridgespans from 85 to 200 light weight members significantly more fabrication and connecting steel more complicated erection procedures truss can be above or below deck modern timber bridges pedestrian bridges design codes and specifications truss bridges pony truss, bowstring or. Abstract the purpose of this example is to illustrate the use of the aashto lrfd bridge design for. U oatmeal containers could be transformed into arches.
It comes with some predesigned projects including bridge 3 trusses with forces, one truss tension, vaulted parallel chord, etc. Since the design truss has a long span, design sections will be chosen from double angle sections rather than single angle sections, which are chosen for smaller trusses. Bridge truss design by influence line free pdf file sharing. Its format is predicated on the assumption that effective design and construction details com mon to conventional construction will also be applied. This design example was edited in 2012 by hdr engineering, inc. Engineers consider many factors in bridge design, including the maximum load it can support and how much deformation the. The project discussed analysis and design of steel truss bridge, the bridge is 40m long and 12 m width and 8 m high, the spaces between the trusses in the roof are various, from the beginning we. The engineering of covered bridges a word about truss. These men, along with other bridge builders who followed them, designed and built many bridges, especially in new england. The objective of this chapter is to figure out the forces being carried by these structures so that as an engineer, you can decide whether the structure can sustain these forces or not.
Timothy palmer 17511821, louis wernwag 17701843, and theodore burr 17711822. Truss is a structure which is commonly used in the construction of bridges. Draw it so that it is between 8 and 11 inches long and between 1. It was easy to fabricate and erect, and the simple design could be repeated for any desired length. Background a truss is a rigid framework whose internal members are connected in a triangular pattern. A truss bridge is built from two trusses one on either side connected by a horizontal bridge deck. Bowstring truss patented in 1841, bowstring is one of the most popular truss designs for smaller truss bridges.
Bridge types tr sstruss system of straight, connected elements used to resist load commonly seen as through truss or deck truss popular in 19th and early 20th centuries constructed of wrougg,ht iron, steel, or timber. Aesthetics of bridge design fritz leonhardt professor, technische hochschule stuttgart stuttgart, germany there is an old latin saying. You may use a successful design from west point bridge design or an existing bridge. Truss gusset plates wahid albert, pe nysdot office of structures october 2008. Given that a triangle cannot be distorted by stress, a truss gives a stable form capable of supporting considerable external loads over a large span. On graph paper, draw the side view of your truss bridge. This bridges design and success were made possible as new materials and construction techniques were developed. It comes with some predesigned projects including bridge 3 trusses with forces, one trusstension, vaulted parallel chord, etc. We were to come up with a prototype using wood craft sticks and white elmers glue. What are truss bridge designs and how do they really work. The engineering of covered bridges a word about truss types. Theodore burr came up with a design that was used in many iconic.