The content of diploma thesis is design of the construction of steel footbridge for pedestrians and cyclists. The footbridge is across the railway in Kyjov. The design will be processed in two options of structure. The selected option will be developed in greater detail. The span of footbridge is 35 m and the width is 3 m. The contruction is made by two arched beams which are connected to the bridge deck by suspenders. The stability of the construction is provided by longitudinal bracing under the bridge deck and the bracing between the arched beams. The assessment of the structure was made according to valid standards.

The subject of this diploma’s thesis is design of the footbridge over Radlická street in Prague. Total length of the footbridge is about 90 m. Three variant designs were made with different systems of static construction. Based on the multi-criteria analysis, the most suitable variant was chosen. The variant A, a continuous truss beam, was chosen for detailed design. It is a truss footbridge with a lower orthotropic deck without a wind bracing. The stability of the upper chord is secured by frame stiffness of verticals and stiffness of the floor beam. Detailed static calculation includes assessment of load-bearing parts of the structure and assessment of welds. The structure is made of steel class S335. Assessment and dimensioning were designed according to valid standards ČSN EN 1990-1993.

<div>Several truck fires have occurred in recent years involving bridges with reinforced and prestressed concrete components. If the fire burns for a significant period of time (15 minutes or more), bridge inspectors and engineers must determine if the exposure to elevated temperature has reduced the strength and serviceability of the concrete components. Little guidance is available, however, correlating the results of field inspections with the actual condition of the reinforced/prestressed concrete elements. This dissertation presents the results of a research program conducted to develop rational guidance for inspectors and engineers to evaluate concrete bridge elements after a fire event and help them make informed decisions regarding the future status of the bridge. <br></div><div><br></div><div>The research program includes tests on portions of a reinforced concrete deck and three full-scaled AASHTO Type I prestressed girders acquired from a decommissioned highway bridge. In addition, six pretensioned concrete prismatic beam specimens with varying levels of prestress were fabricated and tested. The specimens had cross-sectional dimensions of 8 in. by 8 in. and were designed to simulate the bottom flanges of common I-shaped prestressed concrete bridge girders. The deck specimens and four (of the six) concrete beam specimens were subjected to elevated temperatures using radiation-based heaters. Two (of the six) prismatic specimens built in the laboratory were subjected to a hydrocarbon pool fire test conducted in the field for using approximately 135 gallons of kerosene. The concrete temperature profiles and the deformations of the specimens were measured using thermocouple trees and displacement transducers, respectively. Concrete samples were also cored and examined using various methods (DSC and SEM) to correlate microstructure degradation (microcracking, dehydration of C-S-H, decomposition of calcium hydroxide, etc.) with the measured temperatures through the depth of the specimens. <br></div><div><br></div><div>To evaluate the residual loading-carrying capacities of prestressed concrete girders after being subjected to fire, a hydrocarbon pool fire test was performed on two decommissioned AASHTO Type I girders in the field. Load tests were then conducted on the prestressed girders under both ambient and post-fire conditions. After structural testing, material tests were also conducted on concrete cores taken from the girders to evaluate the post-fire concrete microstructure alteration. Furthermore, three-dimensional finite element models were developed to predict the residual load-carrying capacities and overall structural responses of prestressed concrete bridge girders after being exposed to fire. Results from the numerical models generally agree favorably with experimental observations and provide insights into the behavior of the specimens. A parametric study was performed using the benchmarked finite element models to expand the database and establish design recommendations further. Capacity influence lines for load-carrying capacities and structural stiffness were developed and discussed.</div><div><br></div><div>Based on the results from this research, guidelines for the post-fire assessment of prestressed concrete bridges are included in this dissertation along with a step-by-step checklist. Bridge inspectors can infer the extent of damage to prestressed concrete bridge girders in the event of a fire and develop a post-fire assessment plan cognizant of the findings. In most cases, no more than 1.0 in. of the concrete from the exposed surface undergoes material damage / deterioration due to loss of CH, cracking, and spalling. The impact on the strength of prestressed concrete girders is relatively minor based on experimental results. Their initial stiffness, however, will likely be reduced. <br> </div><br>

This essay is a bachelor thesis written for the Degree Program in Constructional Engineering and Design at The Royal Institute of Technology (KTH). This thesis was an assignment given by WSP Sweden and their bridge and water department. The purpose of this report is to conduct an examination on the Life Cycle Cost (LCC) on a prestressed glulam deck bridge and a composite bridge in the early stages of the design phase. This report illuminates the factors that are most crucial in a LCC-calculation for the selected overpasses, and provides an overview regarding which overpass is most efficient from an economic standpoint. The LCC has been calculated based on an 80-year lifespan for the prestressed glulam deck bridge and a 120-year lifespan for the composite bridge. The cost of investment, operating, maintaining and finally the demolition cost was all considered as well. The bridge works that were examined are real life projects in an early stage of the design phase with plans to be built. In the results, the LCC-analysis shows a clear difference in life cycle costs between the prestressed glulam deck bridge and the composite bridge and show that the cost of investment is the most decisive cost during the bridges’ lifespans. The LCC-calculations show that the total life cycle cost for a prestressed glulam deck bridge is higher than the composite bridges’ total life cycle cost.

<p>  </p> <p>During the construction of a bridge, more specifically a concrete bridge deck, there are sometimes defects in materials or workmanship, resulting in what is called a construction defect. These defects can have a large impact on the lifecycle performance of the bridge deck, potentially leading to more preventative and reactive maintenance actions over time and thus a larger monetary investment by the bridge owner. Bridge asset managers utilize prediction software to inform their annual budgetary needs, however this prediction software traditionally relies only on historical condition rating data for its predictions. When attempting to understand how deterioration of a bridge deck changes with the influence of construction defects, utilizing the current prediction software is not appropriate as there is not enough historical data available to ensure accuracy of the prediction. There are numerical modeling approaches available that capture the internal physical and chemical deterioration processes, and these models can account for the change in deterioration when construction defects are present. There are also numerical models available that capture the effect of external factors that may be affecting the deterioration patterns of the bridge deck, in parallel to the internal processes. The goal of this study is to combine a mechanistic model capturing the internal physical and chemical processes associated with deterioration of a concrete bridge deck, with a model that is built strictly from historical condition rating data, in order to predict the changes in condition rating prediction of a bridge deck for a standard construction case versus a substandard construction case. Being able to measure the change in prediction of deterioration when construction defects are present then allows for quantifying the additional cost that would be required to maintain the defective bridge deck which is also presented. </p>

The subject of this thesis is the evaluation of hydrodinamic load on a physical model of a bridge deck, especially to find the relation between the median and extreme quantiles of each hydrodanamic load part and to evaluate the influence, which has the shape of the bridge deck on the size of this load. Relations, that was found may be used to determine characteristic values of loads, caused by water flow, for example, when designing the bridge bearings.

The diploma thesis deals with experimental determination of hydrodynamic load on the overflowed bridge deck model. In the first part of the thesis the author describes the analysis of the problem together with the basic physical laws and principles that are used or assumed in the measurement itself. In the second part the author describes the measurements in the laboratory of the Faculty of Civil Engineering and its gradual processing. At the end of the work are described the results of measurement, their comparison with numerical modeling, other authors and their possible use in practice.

The thesis deals with design and static assessment of the steel railway bridge with a span 36,6 m. The bridge is located on the two-track corridor line Košice - Púchov. It consists of two bridge structures connected by a longitudinal expansion joint. The main construction consists of four solid welded beams mounted on steel calotte bearings. The bridge deck is the top with a tub for the track bed, which is continuous at the site of the bridge. Bridging the bridge is secured by a track bed and a horizontal and lateral truss bracing. On both sides of the bridge are pedestrian walkways with a width of 1,5 m.

The aim of this bachelor thesis is variant design and assessment of loadbearing structure of steel footbridge over I/11 route. Main superstructure will have two steel arched beams joined with lower orthotropic deck using suspenders in the „V“ shape. For assessment of superstructure a three-dimensional structural computational model was created in software Dlubal RFEM 5.20. The span of the footbridge is 48,71 m, free width is 4 m, height is 7,5 m. The structure was designed according to currently valid standarts to the ultimate limit state and serviceability limit state. Supporting elements are designed from steel of class S355.

This diploma thesis contains a study of current composite structure of footbridge and in part II design and assessment of steel structure of footbridge for pedestrians and cyclists placed on current footbridge location. Current footbridge is located on "nábřeží Dukelských hrdinů" in Rožnov pod Radhoštěm. In part I, assessment of the current composite structure of footbridge is done, using ČSN and ČSN EN standards for adjusted static behavior of the structure. Comparison of both assessments is made and also with an original assessment from 1988. In part II, design and assessment of steel structure of footbridge placed on currents footbridge location described in part I is done.The structure was designed as two vierendeels trusses connected with cross beams, supporting concrete bridge deck. 9 variants were examined, differing with truss height and the number of verticals. Detailed design and assessment for parts of the structure is done for the chosen variant.