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Streets-in-the sky is a form of multi-storey working class housing which is important in today's society for two reasons. Firstly, because street-deck housing became especially popular during the post-war rebuilding of British cities following the inter-war introduction of the idea and the successful development of the Park Hill scheme in Sheffield in the 1950s. In the 1960s, especially in the second half of the decade, the design professions, several leading local authorities, and central government undertook the development of street-deck housing throughout the United Kingdom. It proved to be especially popular, outside London, in the economically declining or static regions of England; relatively little being built in Scotland, Wales or Northern Ireland. Hence streets-in-the-sky tended to be developed in those English regions where the basic export industries of coal, iron and steel, shipbuilding and textiles were subject to the most comprehensive state-controlled restructuring. The large scale public investment and labour resistance to change associated with industrial restructuring were therefore often partnered by a form of high density housing more acceptable to the financially overburdened local authority and the 'anti-flats' culture of the English than the economically and socially unpopular tower block. Following the building programme there was a decline in the fortunes of modern architecture, the labour movement and the United Kingdom economy. With that decline came a pronounced reduction in the quantity and quality of this type of urban housing. In the 1970s, the poor construction, difficult access, anti-social use of the 'street' and the stigma attached to living on the estates usually led to the schemes becoming especially difficult-to-let. Thus, in a quarter of a century, this particular housing form had changed from being a central element in the modern architectural urban utopia to its opposite - a microcosm of the problems facing British cities in their decline. Secondly street-deck housing is important because its history brings to light the contradictions between different ideas and different political and economic interests, and reveals how these contradictions can be temporarily overcome by the development of a particular form of urban housing. These patterns of conflict and consensus are not fully comprehended by existing "counter-revolutionary" and "revolutionary" theories of urban form and change. In the former case we have tried to show how the assumptions of so called 'postmodernism' are incorrect. And in the latter, how a far broader interpretation of the totality (base and superstructure) is necessary as a basis to knowledge and action.

Development of continuity between precast prestressed bridge girders by post-tensioning the insitu top slab In the regions of hogging moment is a relatively new technique which forms the basis for this research study. Compared to the more conventional method of using reinforcing steel in the slab over the interior supports, prestressed slabs will ensure a crack free more durable bridge deck, and will therefore reduce the maintenance costs. The effect that such a slab has on flexural and shear behaviour of the bridge deck has been studied both analytically and experimentally by considering composite beams based on M-8 standard precast beam section. Comparison of the design of bridge decks with a prestressed slab and a reinforced concrete slab indicated that a partially prestressed slab with a prestress considering up to 50% of the live load will ensure the slab remains crack free under total service load. Although secondary effects and the two stage construction of such a slab tend to increase the prestress requirement for the slab, the same two effects considerably reduce the positive midspan moments, resulting in a decrease in the prestress required in the precast beams (and thus a possible increase in the span range) for given standard precast beam sections. The experimental investigation consisted of testing eleven 1/3-scale M-8 continuous composite beams in two series, Series-A and Series-B. Series A, in which three beams were tested as double cantilevers was planned to study the effects of prestressed slab on overall flexural behaviour. A considerable improvement in crack control under service loads and a higher ratio of measured to calculated ultimate moment capacity was obtained in beams with a prestressed slab. The continuity developed using insitu prestressed slabs was very effective at all levels of loading. Recommendations have been made for the flexural design of continuous bridge decks with this type of prestressed slabs. In Series B, effect of prestressed slabs on shear strength at the continuity connection has been studied. A considerable increase in web shear cracking load was obtained for beams with prestressed slabs, resulting in a decrease In the amount of shear reinforcement required for such beams. The different methods of predicting web shear cracking strength and web crushing strength according to current design codes were compared with experimental values, and based on the results, recommendations for the design for vertical shear of composite beams subjected to hogging moments have been made.

Thesis (M. Phil.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 160-161).

The topic of Master´s thesis is the design of steel foodbridge over the Morava river in Olomouc. Construction was carried out in two variants, one of which was chosen as the best option arched foodbridge is suspended orthotropic deck. Span bridge is 40m. Calculation of construction was carried out Scia Engineer 2015

A bridge with precast bridge deck panels was built at the Virginia Tech Structures Laboratory to examine constructability issues, creep and shrinkage behavior, and strength and fatigue performance of transverse joints, different types of shear connectors, and different shear pocket spacings. The bridge consisted of two AASHTO type II girders, 40 ft long and simply supported, and five precast bridge deck panels. Two of the transverse joints were epoxied male-female joints and the other two transverse joints were grouted female-female joints. Two different pocket spacings were studied: 4 ft pocket spacing and 2 ft pocket spacing. Two different shear connector types were studied: hooked reinforcing bars and a new shear stud detail that can be used with concrete girders. The construction process was well documented. The change in strain in the girders and deck was examined and compared to a finite element model to examine the effects of differential creep and shrinkage. After the finite element model verification study, the model was used to predict the long term stresses in the deck and determine if the initial level of post-tensioning was adequate to keep the transverse joints in compression throughout the estimated service life of the bridge. Cyclic loading tests and shear and flexural strength tests were performed to examine performance of the different pocket spacings, shear connector types and transverse joint configurations. A finite element study examined the accuracy of the AASHTO LRFD shear friction equation for the design of the horizontal shear connectors. The initial level of post-tensioning in the bridge was adequate to keep the transverse joints in compression throughout the service life of the bridge. Both types of pocket spacings and shear connectors performed exceptionally well. The AASHTO LRFD shear friction equation was shown to be applicable to deck panel systems and was conservative for determining the number of shear connectors required in each pocket. A recommended design and detailing procedure was provided for the shear connectors and shear pockets. / Ph. D.

A set of experimental tests were performed at Virginia Tech to investigate transverse joints and blockouts on full depth concrete bridge deck panels. The joints were designed on a deck replacement project for a rural three span continuous steel girder bridge in Virginia. Two cast-in-place and four post-tensioned joints were designed and tested in cyclical loading. Each joint was tested on a full scale two girder setup in negative bending with a simulated HS-20 vehicle. The blockouts were built as hollow concrete rings filled with grout and left to shrink under ambient conditions. Thirteen combinations of different surface conditions and grouts were designed to test the bond strength between the materials. The strain profile, cracking patterns, and ponding results were measured for all specimens. A finite element analysis was performed and calibrated with the laboratory results. The cast-in-place joints and the two post-tensioned joints with 1.15 MPa (167 psi) of initial stress experienced cracking and leaked water by the end of the tests. The two post-tensioned joints with 2.34 MPa (340 psi) initial stress kept the deck near a tensile stress of 1.5√(𝑓'c) and performed the best. These transverse joints did not leak water, did not have full depth cracking, and maintained a nearly linear strain distribution throughout the design life. Full depth deck panel may be effectively used on continuous bridges if a sufficient amount of post-tensioning force is applied to the transverse joints. The finite element model provides a design tool to estimate the post-tensioning force needed to keep the tensile stresses below the cracking limit. The blockouts with a roughened surface or an epoxy and a grout equivalent to Five Star Highway Patch grout had the highest bond stresses, did not leak water, and had smaller cracks at the grout-concrete interface than the control samples. A minimum bond strength of 2.5√(𝑓'c) was maintained for all of the specimens with a grout equivalent to Five Star Highway Patch. A pea gravel additive in the grout reduced shrinkage and reduced the bond strength. The finite element model provides a design tool to estimate cracking at the grout-surface interface. / Ph. D.

As the aging bridges and infrastructure within the US continue to deteriorate, traffic delays due to construction will become more and more common. One method that can reduce delays due to bridge construction is to use precast deck panels. Precast deck panels can significantly reduce the overall length of the construction project. The panels can be manufactured ahead of time, and with higher quality control than is possible in the field. One of the reasons precast deck panels are not widely accepted is because of a lack of research concerning the required post-tensioning force, shear stud pocket placement, and proper joint design. In a recent dissertation (Swenty 2009) numerous recommendations were made for joint design, shear stud pocket design, and post-tensioning force for full-depth precast deck panel bridges. Design drawings were included for the replacement of a bridge located in Scott County, Virginia. The research in this report focuses on the short-term and long-term testing of this bridge. The short-term testing involved performing a live load test in which two trucks of known weight and dimensions were positioned on the bridge in order to maximize the negative moment at the joints over the piers and document strains and deflections at a number of other critical locations. The long-term testing involved monitoring the strains within the deck and on one of the six girders for a number of months in order to document the changes in strain due to creep and shrinkage. The results of these tests were compared to 2D beam-line models and to the parametric study results of Bowers' research on prestress loss within full-depth precast deck panel bridges. It was determined that the bridge was acting compositely and that the post-tensioning force was sufficient in keeping the joints in compression during testing. / Master of Science

The extreme motion and load of ships have been assessed using a linear frequency domain method or a linear energy spectral method and RAOs, which may be too approximate to be used for estimation of ship motion in severest seas. The new technology uses simulation in the time domain to deal with the non-linear responses to the random seas. However, the current simulation technique has been successful only up to the sea state of 7 (“high seas”), defined by the significant wave height of 9 meters. The above cannot provide the extreme wave loads and motions for seas higher than the sea state 7. The ultimate goal of this work would be to develop a new technique that can simulate responses to the seas of states 8 and 9. The objective of the present study is to simulate the vertical relative motion and wave topping of a moored ship in the time domain by varying the significant wave heights. The analysis was able to predict with a fair accuracy the relative motion characteristics of a freely floating body in the head and beam sea conditions. The resonance aspects and its significance in the overall response are also analyzed.

The damaging effects of hurricane landfall on US coastal bridges have been studied using physical model testing. Hurricane bridge damage and failure susceptibility has become very evident, especially during hurricane seasons 2004 and 2005 in the Gulf of Mexico. The combination of storm surge and high waves caused by a hurricane can produce substantial loads on bridge decks leading to complete bridge failure. Several theoretical methods have been developed to estimate these forces but have not been tested in a laboratory setting for a typical bridge section. Experiments were done using a large-scale 3-D wave basin located at the Haynes Coastal Engineering Laboratory at Texas A&M University to provide estimates of the horizontal and vertical forces for several conditions to compare with the forces predicted with the existing models. The wave force results show no strong correlation between the actual force measured and the predicted force of existing theoretical methods. A new method is derived from the existing theoretical methods. This model shows a strong correlation with both the measured horizontal and vertical forces.