Aspects of analysis of simply supported bridge decks

The above sectios demonstrate the different sections at midspan of the box girder, the end detail of the box girder having thicker dimension and blocked by end diaphragms improving on their shear capacities and the tapering section shows transision between end and mid girder sections. Construction Stage 1 Simply Support Span girders with no wet joints Actual maximum stress = 11.28Mpa Permissible tensile stress at Construction stage= 1.00Mpa (BS5400) and, Permissible compressive stress = 0.4fck=16.0Mpa Construction Stage 2 Semicontinous Box Girders with Wet joints cast and harden Semi-continous PCC PSC Box Girders at service stage Actual maximum stress = 11.22Mpa Permissible tensile stress at this stage= 0.36*sqrt(fck) = 2.3Mpa Permissible compressive stress = 0.6fck= 24.0Mpa Actual maximum Compressive stress = 12.40Mpa and tensile = 2.73Mpa Permissible tensile stress at this stage= 0.36*sqrt(fck) = 2.3Mpa Permissible compressive stress = 0.6fck= 24.0Mpa

Spatial structure is a truss-like, lightweight and rigid structure with a regular geometric form. Usually from these structures is used in covering of long-span roofs. But these structures due to the lightness, ease and expedite of implementation are a suitable replacement for bridge deck. However steel and concrete is commonly used to build bridge deck, but heavy weight of steel and concrete decks and impossibility of making them as long-span bridge deck is caused engineers to thinks about new material that besides lightness and ease of implementation, provide an acceptable resistance against applied loads including both dead load and dynamic load caused by the passage of motor vehicles. Therefore, the purpose of this paper is design and analysis bridge deck that’s made of double-layer spatial frames compared with steel and concrete deck. Then allowable deflections due to dead and live loads, weight of bridge in any model and also economic and environmental aspects of this idea is checked. As a result, it can be said that the use of spatial structures in bridge deck is lead to build bridge with long spans, reducing the material and consequently reducing the structural weight and economic savings. For geometric shape of the spatial structure bridge is used of Formian 2.0 software and for analysis of bridges is used of SAP2000 with finite element method (FEM).

Construction and Building Materials, 2004

The purpose of this paper is to present fatigue and strength experimental qualifications performed for an all-composite bridge deck. This bridge deck, made up of fiber-reinforced polymer (FRP) was installed on the campus at University of Missouri at Rolla on July 29th, 2000. The materials used for the fabrication of this 30 foot (9.144 m) long by 9 foot (2.743 m) wide deck were 3 inches (76.2 mm) pultruded square hollow glass and carbon FRP tubes of varying lengths. These tubes were bonded using an epoxy adhesive and mechanically fastened together using screws in seven different layers to form the bridge deck with tubes running both longitudinal and transverse to the traffic direction. The cross-section of the deck was in the form of four identical I-beams running along the length of the bridge. Fatigue and failure tests were conducted on a 30 foot (9.144 m) long by 2 foot (609.6 mm) wide prototype deck sample, equivalent to a quarter portion of the bridge deck. The loads for these tests were computed so as to meet American Association of State Highway and Transportation Officials (AASHTO) H-20 truckload requirements based on strength and maximum deflection. The sample was fatigued to 2 million cycles under service loading and a nominal frequency of 4 Hz. Stiffness changes were monitored by periodically interrupting the run to perform a quasi-static test to service load. Results from these tests indicated no loss in stiffness up to 2 million cycles. Following the fatigue testing, the test sample was tested to failure and no loss in strength was observed. The testing program, specimen detail, experimental setup and instrumentation, testing procedure, and the results of these tests are discussed in detail. A finite-element model of the laboratory test was also developed. The results from the model showed good correlation to deflections and longitudinal strains measured during the tests. The design of the bridge deck has been discussed in detail.

Advances in Civil Engineering, 2012

PARAMETRIC STUDY OF THE STRUCTURAL BEHAVIOR OF HORIZONTALLY CURVED BRIDGE DECK, 2016

This paper investigates the impact of the following parameters on the structural behavior of horizontally curved bridge decks: A-The analytical modeling method, B-The radius of curvature, C-The number of internal cross girders, and D-The thickness of deck slab. The results of the different analytical modeling technique are compared to experimental results by conducting a load test on a physical model at the structural lab of the American University in Cairo cairo as a part of a research for curved bridges directed by the author.The remaining parameters of this study are investigated using a typical curved bridge deck commonly used in real projects. The impact of these parameters is addressed by the change in straining actions and the deflection of the main girders of the bridges.

Scenario You are a graduate structural engineer working for a major consultancy company that is an acknowledged world-leader in its field. The company employs 6000 staff and operates from 70 offices in 40 countries throughout the world and has an annual turnover of some £500 million per year. You are working within a team of specialist bridge design engineers who are responsible for a large portfolio of bridges being designed for construction in the UK and in a number of overseas developing countries. You have been given the task of designing a steel bridge to carry a railway across a major motorway in the South of England. The form of the bridge will be a triangulated pin-jointed steel truss (see photo 4 below) – this has been determined to be the most appropriate form of bridge chosen from the many different types of bridge structure used throughout the world. As part of the initial design process you are required to analyse the proposed bridge and determine the forces within each of the bridge members. The calculation of these forces will subsequently lead to the selection of the most appropriate size of steel section for the members and the detailed design of the connections where the members meet. In this exercise the learner will apply techniques for the solution of simultaneous equations using methods, including matrix techniques, that form the basis of the calculations that would be undertaken by the structural engineer, often now a days carried out using powerful computer software packages. Importance of Exemplar in Real Life Bridges range from small structures such as simple footbridges to iconic structures such as the Humber Bridge which, when opened in 1981, held a 17 year world record for being the longest single span suspension bridge in the world. Built at a cost in excess of £150m its world record and cost of construction have since been far exceeded – the record for the longest span suspension bridge currently being the Akashi-Kaikyō Bridge in Japan which has a suspended centre span of nearly 2000 metres, although such records are being continuously broken. Although the construction of such iconic bridges is often a statement of national pride the decision to construct any bridge is usually based on social and economic criteria. For example, the construction of the Humber Bridge provided access to two areas of the UK which were geographically remote and provided the opportunity for commercial, industrial and tourist development and saved many millions of vehicle miles in providing a short transit route between both sides of the Humber estuary. Such potential developments and financial savings are the justification for the huge cost investments made in building bridges throughout the world although factored into such cost considerations has to be the ongoing cost of maintenance and repair over the life span of the bridge. Bridges are constructed in a wide range of materials including masonry, timber, steel, reinforced concrete, prestressed concrete and composite construction. They are built in a variety of different forms including simple beams, trusses, arches, suspension, and cable-stayed structures. The choice of material and structural form depends on a wide range of factors such as the load to be carried including the weight of vehicles, the span length of the bridge, the construction and maintenance costs, the visual impact and so on. Whatever the final choice the Structural Engineer makes, either individually or as part of a design team has an important role to play in ensuring the most appropriate choice of structure and materials and in ensuring the structural integrity of the bridge during construction and throughout its working life. Examples of different types of bridges can be seen in figures 1 to 4. Figure 4 illustrates the type of bridge that we will be considering in this exercise. It is fabricated from structural steel sections to form a bridge which is simply supported i.e resting and supported on a supporting structure at either end.-1

2006

©2006-2007 Asian Research Publishing Network (ARPN). All rights reserved. ... EFFECT ON SUPPORT REACTIONS OF T-BEAM SKEW BRIDGE DECKS ... Trilok Gupta1 and Anurag Misra2 1Department of Civil Engineering, CTAE, Udaipur, Rajasthan, India 2Department of ...

The object of the paper is the study of the representativity of the grillage models with which different types of bridge decks are schematized. First, the theoretical principles on which this kind of modelling is based are recalled; the equivalent condition between bi-dimensional continuous elements and corresponding grillage models are imposed through the use of a kinematics and an energetic criterion. Secondly, the same technique is generalized to three-dimensional structures and specialized to the case of cellular decks. For this kind of deck, structural behaviours usually neglected by the current technical approaches, like shear lag, distortion and warping, are considered. The paper presents some methods introducing these effects in a grillage analysis; these methods provide a series of criteria with which it’s possible to define the rigidities of the equivalent model. These criteria are applied and compared with finite element solutions. Finally, a series of applications are executed in order to verify the efficiency and the accuracy of this kind of approach.

2010

2019

Revista IBRACON de Estruturas e Materiais

In systems of suspended cable bridges, the cable-stayed bridges have been widely used because of its capacity to overcome large spans and not require large areas of support during their execution, minimizing interference with existing vehicle flow or overcoming large spans in rivers and channels that require space to the passage of vessels. In addition to this structural advantages, they are aesthetically well accepted by society, valuing the urban space and often making it a landmark. This paper aims to describe the influence of unilateral suspension of decks on the behavior of cable-stayed bridges with curved decks through structural models in order to evaluate whether structural gains or losses are relevant to project considerations. Results indicated that stresses variation in the deck depends not only on the position of the cables and their forces (which depends on the stiffness of the deck), but also on the cable itself and the central pylon.

Transportation Research Board 90th Annual MeetingTransportation Research Board, 2010