Three series of tests were conducted on a sandwich plate bridge deck, which consisted of two steel plates and an elastomer core. The first series of testing was conducted by applying a static load on a full scale sandwich plate bridge deck panel. Local strains and deflections were measured to determine the panel's behavior under two loading conditions. Next, fatigue tests were performed on the longitudinal weld between two sandwich plate panels. Two connections were tested to 10 million cycles, one connection was tested to 5 million cycles, and one connection was tested to 100,000 cycles. The fatigue class of the weld was determined and an S-N curve was created for the longitudinal weld group. Finally, a series of experiments was performed on a half scale continuous bridge deck specimen. The maximum positive and negative flexural bending moments were calculated and the torsional properties were examined. Finite element models were created for every load case in a given test series to predict local strains and deflections. All finite element analyses were preformed by Intelligent Engineering, Ltd. A comparison of measured values and analytical values was preformed for each test series. Most measured values were within five to ten percent of the predicted values. Shear lag in the half scale bridge was studied, and an effective width to be used for design purposes was determined. The effective width of the half scale simple span sandwich plate bridge deck was determined to be the physical width. Finally, supplemental research is recommended and conclusions are drawn. / Master of Science

Orthotropic steel deck has been widely used over the decades especially on long-span bridges due to its light weight and fast construction. However fatigue cracking problems on the welds have been observed in many countries. Rib-to-deck welds need special care since they are directly under wheel loads, which cause large local stress variations and stress reversals. Currently the only requirement by AASHTO bridge code is that the rib-to-deck welds need to be fabricated as one-sided partial penetration welds with minimum penetration of 80% into the rib wall thickness. However considering the thin rib plate thickness, it is very difficult to achieve this penetration without a "melt-through" or "blow-through" defect. Large cost has been caused for the repair. However recent research has found that the fatigue performance of the rib-to-deck weld is not directly related to its penetration. Other factors contribute to the fatigue performance as well. Therefore, alternative requirements which are more cost-effective and rational are desired. The objective of this research is to provide recommendations to the design and fabrication of rib-to-deck welds by investigating their fatigue performance with different weld dimensions, penetrations, and welding processes. Fatigue tests were performed to 95 full-scale single-rib deck segments in 8 specimen series fabricated with different welding processes and root gap openness. Specimens were tested under cyclic loads till failure. Three failure modes were observed on both weld toes and the weld root. Test results showed that the fatigue performance was more affected by other factors such as failure mode, R-ratio and root gap openness, rather than the weld penetration. The failure cycles were recorded for the following S-N curve analysis. Finite element analysis was performed to determine the stress state on the fatigue cracking locations. Special considerations were made for the application of hot-spot stress methodology, which post-processes the FEA results to calculate the stress values at cracking locations with the structural configuration taken into account. The hot-spot stress range values were derived and adjusted accounting for the fabrication and test error. Hot-spot S-N curves were established for each specimen series. Statistical analyses were performed to study in depth the effect of weld dimensions and test scenarios. Multiple linear regression (MLR) was performed to investigate the effects of different weld dimensions; and multi-way analysis of covariance (Multi-way ANCOVA) for the effects of specimen series, failure mode, R-ratio and weld root gap. It was found that the weld toe size was more relevant to the fatigue performance, other than the weld penetration. The failure mode and R-ratio were very influential on the fatigue performance. Recommendations to the weld geometry were proposed based on the MLR model fitting. S-N data were re-categorized based on ANCOVA results and the lower-bound S-N curve was established. AASHTO C curve was recommended for the deck design. / Master of Science

The diploma thesis is focused on a design and appraisal of a steel load bearing construction of footbridge. The footbridge builds a new bridge across the river Ostravice in Sviadnov at Frýdek-Místek. The main subject of the diploma thesis was preparation of three variants for the footbridge. All variants were evaluated and the best one was elaborated in depth. It is a footbridge with a total span of 57 metres with a load bearing construction created two arches bent down to each orther. There is an orthotropic bridge deck with main outer lenghthways girders on the arches.

The thesis deals with the variant design of the steel structure of single-track railway bridge on the line Tišnov – Nové Město na Moravě. The task is bridging the local road by a bridge structure with one field. Length of the bridge is 40 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.

The diploma thesis is focused on the design of a new steel structure of a single-track railway bridge with bottom bridge deck. The solved bridge construction is located on line No. 123 between Nemšová and Trenčianska Teplá at the point, where the line crosses over the river Váh. The existing bridge on the line has a span of 50 + 50 + 50 + 50 m. The assignment was processed in five variants of a steel bridge structure with a bottom orthotropic deck. Each variant has a different static system, a different number of fields and a different type of superstructure. The comparison of variants was performed using multicriterial evaluation based on selected criteria. The most suitable variant was elaborated in more detail. The calculations were performed according to valid ČSN EN standards.