[Truncated abstract] The Arabian Gulf oil and gas production reserves have made it one of the world's strategic producers since early 1960s, with many of the existing platforms stretched beyond their original design life. Advances in drilling technology and reservoir assessments have extended the requirement for the service life of those existing platforms even further. Extension of the life span of an existing platform requires satisfactory reassessment of its various structural components, including piled foundations. The American Petroleum Institute Recommended Practice 2A (API RP2A) is commonly used in the Arabian Gulf for reassessment of existing platforms. The API guidelines have been developed for conditions in the Gulf of Mexico, the waters off Alaska and the Pacific and Atlantic seaboards of the USA. However, the Arabian Gulf conditions are fundamentally different to those encountered in US waters. Hence, there is a need to develop guidelines for reassessment of existing offshore structures to account for the specific conditions of the Arabian Gulf. This thesis performs statistical analyses on databases collected during this research from existing platforms to calibrate relevant load and resistance factors for the required guidelines. The developed guidelines are based on established approaches used in developing international codes and standards such as API RP2A-LRFD. The outcome of this research revolves around the following three main issues: 1. Calibration of resistance factors for axial capacity of piles driven in the carbonate soils API RP2A (1993, 2000) does not quantify limiting soil parameters for piles driven in carbonate soils and provides a single factor to predict the capacity of piled foundations. This research identifies a set of limiting engineering parameters and calibrates corresponding capacity reduction factors to predict axial capacity of driven piles in the carbonate soils of the Arabian Gulf. ... This contrasts with Section 'R' of API RP2A (1993, 2000), which focuses on extreme environmental conditions when performing reassessment. The probabilities of failure considered in this research do not include errors and omissions (controlled by quality assurance procedures) or material deterioration (controlled by choice of materials, detailing, protective devices, and inspection and repair procedures) or reliability-based maintenance. Addressing operating overload conditions requires attending to two issues, namely the capacity of piles driven in carbonate soils and OALL, which have been addressed in this research. The operational overload situation is likely to occur during shutdown condition or during drilling or work over activities where significant OALL are usually applied to platform decks. Such operational overload can be managed by placing signs at various open areas on the platform nominating the maximum load limits (kPa), introducing procedures that ensure that maximum load limits are not exceeded during operation and management of human behavior by reinforcing the importance of following the procedures. The outcomes of this research are expected to have a profound influence on reassessment of existing platforms in the Arabian Gulf.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012. / Cataloged from PDF version of thesis. / Includes bibliographical references (p. 115-117) / Highway bridges are exposed to numerous elemental and loading issues that are extremely difficult for a designer to anticipate and account for during design. The current state of practice is to design a bridge deck for a certain life span and then turn the bridge over to maintenance personnel who attempt to prolong the life of the deck through a variety of repair and rehabilitation measures. These repair measures are rarely, if ever, considered during the design process of the bridge deck. Numerous researchers have looked at making bridges, specifically decks, more repairable. The majority of these research efforts have focused on the bridge deck system as a whole. Other researchers have looked at individual elements of the bridge deck to girder connection to see if the required strength could be achieved while making the connections easier to take apart. One of the main components in the bridge deck to girder system is the steel shear stud connection, which is used to create composite action between the deck and the girder. Numerous researchers have studied this connection from a strength perspective, and the strength equations for the shear connection have been codified. Shear connections using headless studs have been researched as well, but always as a part of a larger deck to girder connection system. The headless stud has never been researched to see how it responds to a shear loading. This study looks at headless studs with varying levels of debonding along the stud shaft to analyze the impact on the load resistance that the levels of debonding would have. Granular materials for the shear transfer of load are also looked at. The results show that, as expected, the headless, debonded shear studs can carry less load than a bonded stud, but the difference in load carrying capacity is within the suggested over-estimation range of the codes that other researchers have suggested. These results suggest that the use of headless, debonded shear studs in a deck to girder connection is a feasible way to make that connection more repairable. / Funded by the U.S. Dept. of the Army. / by Berndt F. Spittka / S.M.

Accurately predicting the response of complex bridge structures to strong earthquake ground motion requires the use of sophisticated nonlinear dynamic analysis computer programs not generally available to the bridge design engineer. The analytical tools that have been developed are generally applicable to bridges whose substructures can be idealized as beam-columns. Bridges with wall piers do not belong to this category The major objective of this study is to develop an analysis tool capable of simulating the effects of earthquakes on monolithic concrete wall pier bridges. Thus, after surveying the literature, a mathematical model is developed for the geometrically nonlinear earthquake analysis of wall pier bridges. Mixed plate elements are used to model the wall pier. The plate element has eight nodes and the degrees of freedom per node are three displacements and three moments. Beam elements are used to model the bridge deck. The beam element accounts for shear deformation and it has two nodes with three displacements and three rotations as degrees of freedom per node. A transitional element is used to join the beam elements to the plate elements. The equation of dynamic equilibrium is solved using the Newmark method with modified Newton-Raphson type iteration at each time step. The mixed plate element is used to model two plate structures and the results are compared with analytical and other finite element solutions. A two span wall pier bridge is modeled using the structural elements developed in this study. The digitized time history for the N-S component of the El Centro Earthquake of May 18, 1940, is used to seismically excite the bridge model. / Ph. D.