Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2001. / Includes bibliographical references (leaves 91-93). / Most problems cited in papers dealing with project success factors are often linked to the responsibility of particular players in the construction phase, rather than to the relations among them and with their environment. Challenging the current belief that "dividing is ruling", this new vision groups problems seemingly different in nature, and provides, from their analysis, a unified set of recommendations that, if applied, could help drastically reduce unpredictability of the outcome of a project and boost productivity. Yet, and it is confirmed by the few articles that have been written about this approach, little has been done on the construction field. The appearance of a new form of project management, lean construction, and the verifiable results of improvement it triggers, offers the interface perspective a more comprehensive and supportive environment, in which it can be more easily developed, implemented and perfected. This study focuses on what should be considered the three most important interfaces during the construction phase of the project, and will compare the improvements suggested by this approach to the principles of lean construction, to support the utility of this new way of perceiving problems. / by Benoit Martin. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996. / Includes bibliographical references (leaves 389-294). / by Boonchai Ukritchon. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, February 2004. / Includes bibliographical references (p. 209-213). / The sample disturbance problem for different geomaterials is reviewed in this thesis. A general discussion on the disturbance sources and complexities of the disturbance problem is followed by detailed reviews on disturbance mechanisms and effects in soil and rock. This investigation leads to the conclusions that the combination of theoretical and physical modeling is an effective way to study the disturbance problem. Following the discussion of sample disturbance in soil and rock, the main aspects of shale behavior and shale sample disturbance are introduced in order to evaluate the applicability of theoretical and physical modeling in shale. It is shown that the coupled chemical - thermal - poromechanical effects of shale behavior may be a major barrier to a successful application of these modeling methods and to a better handling of sample disturbance. / by Jianyong Pei. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2006. / Includes bibliographical references (p. 115-119). / In the United States, the construction industry accounts for almost 75% of total raw material used. This is an obvious drain on natural resources and has a major impact on the surrounding environment. Construction materials are also responsible for a relatively large portion of the global CO2 emissions. The commercial construction industry is dominated by the use of steel and in-situ concrete as building materials. It is intuitive then, to state that these two materials and their respective production flows have a significant impact on the environment, simply because of the amount of material being produced and consumed in the building industry today. In addition, due to drastic increases in energy prices and potential shortages in the future, the amount of energy consumed in the production of construction materials (embodied energy) and the amount of energy used over a projected life span (operational energy) are becoming increasingly more important to builders, designers, and owners of buildings. The growing trend in the United States, and elsewhere in the world, is towards eco-friendly design. In the last several years, the concrete and steel industries have spent significant resources to promote their material as the optimum solution for sustainable building design. / (cont.) Because natural resource consumption, air emissions, and the amount of embodied energy are all important drivers for the push towards sustainability, this study will compare those factors and quantify the differences between what is necessary for the construction of concrete- and steel-frame structures. The purpose of this thesis is to utilize the Life Cycle Assessment (LCA) method to compare the environmental impacts created by the steel and concrete construction industry at the lowest common performance level, in this case the structural shell of a typical building in a given geographical area. The study will include all major product systems and material flows involved with concrete or steel construction and quantify their impacts in terms of total energy requirement, natural resources consumed, and harmful air emissions, specifically as they relate to global warming potential. / by Timothy Werner Johnson. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000. / Includes bibliographical references. / Polyethylene devices (PEDs), which rely on the partitioning of hydrophobic organic contaminants (HOCs) between water and polyethylene, were shown to be useful for the measurement of dissolved HOCs like polycyclic aromatic hydrocarbons (PAHs) in natural waters. These PEDs allow for the measurement of the fugacity or "fleeing tendency" of such chemicals in water. These dissolved concentrations are of ecotoxicological concern as they reflect the HOC fraction that is driving uptake by the surrounding organisms. Because PEDs require on the order of days to equilibrate in the field, their use provides time-averaged measurements. Laboratory-measured polyethylene-water partition coefficients for two PAHs were: 17,000 ±1000 (mol/LPE)/(mol/Lw) for phenanthrene and 89,000 ± 6000 (mol/LPE)/(mol/Lw) for pyrene. These organic polymer-water partition coefficients were found to be comparable to other organic solvent-water partitioning coefficients. These large coefficients allowed for the measurement of dissolved concentrations as low as 1 pg/L for benzo(a)pyrene and 400 pg/L for phenanthrene in the lower Hudson Estuary. Sampling performed in the lower Hudson Estuary during neap and spring tides revealed increased concentrations of dissolved pyrene and benzo(a)pyrene, but not phenanthrene, during increased sediment resuspension. These data suggest that resuspension events mostly influence the bed-to-water exchange of PAHs with greater hydrophobicities. PAH water concentrations predicted assuming dissolved and sorbed concentrations related via the product, fomKom, where fom is the fraction of organic matter in the suspended sediments and Kom is the organic-matter-normalized solid-water partition coefficient for the PAH of concern, were far from observed concentrations. Adding the influence of soot to the partition model via Kd = fomKom + fse,4Ke, where fse. is the weight fraction of soot carbon in the solid phase and Ke is the soot carbon-water partition coefficient estimated form activated carbon data, yielded predicted concentrations that were much closer to the observed values when PAH partitioning to soot was included in the partitioning model. This finding suggests that soot plays an important role in controlling the cycling of PAHs in the aquatic environment. However, even when the soot partitioning of PAHs was included in the model, the predicted dissolved values were still larger than the measured values. This suggests that the time of particle resuspension is too short to allow for particle-water sorptive equilibrium. Using ratios of source indicative PAHs, it was estimated that 90% of the dissolved PAH fraction was derived from petrogenic sources. In contrast, the same source ratios for the total (dissolved and sorbed) PAH concentrations indicated that only 55% of the total were petrogenically-derived. The observations in this work suggest that efforts to regulate and remediate PAH-contaminated sediments must consider the potential impacts of soot associations of the PAHs. / by Rachel G. Adams. / S.M.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references (page 55). / The unique geometry and indeterminacy of the Collier Memorial make it a highly complex structure to analyze. During the critical vault-lowering phase of the construction of the memorial, joints were monitored to understand where and how the memorial deformed. Joint displacements are aggregated into figures to allow for a visual representation of the joint displacements working in conjunction with one another. With the visualization of the displacement data, it was determined that a hinging mechanism formed in one of the legs. The majority of the self-weight, about 96%, was transferred to the supporting walls in compression during the lowering of the vault. Joint displacements were also used to assess the actual thrust states of two legs to be compared to analytical and numerical models generated during the design phase. The mechanics of the multipolymer shim used as the intermediary between the granite blocks were studied. The joint displacements in combination with the shim mechanics produced thrust values within the minimum and maximum thrust range established by a thrust line analysis. / by William O. Cord. / M. Eng.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references (pages 27-28). / DOC characterization of freshwater is poorly understood at areas of harsh or difficult to access, especially areas like peatland rainforest. In order to figure out the level of DOC transport, an in situ instrument was previously designed to measure the DOC concentration at remote locations. However, the data collected by the instrument is not as meaningful as expected due to the complex environment, high DOC concentration and inner shielding. A new instrument is required to be designed to fulfil the objectives. Like the previous instrument, the new instrument still needs to measure the fluorescence and absorbance data to give an estimation of DOC concentration. There are three LEDs to provide fluorescence measurements, a wideband lamp to provide light for absorbance measurement and a spectrometer to record the resulting spectra. Unlike general in situ fluorometers, the orientation between the excitation source and detector is 90 degrees for the new optical configuration. The new designed optical configuration solves the problem of window obstruction and also successfully prevents the problem of misalignment caused by water turbulence. Furthermore, the instrument also solves the problem of long light path lengths with the new configuration. The instrument was tested to work well in the lab with a range of DOC concentration from 5 ppm to 60 ppm. The recorded data showed a strong positive relationship between fluorescence intensity and concentration of DOC. / by Lu Xu. / M. Eng.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996. / Includes bibliographical references (leaves 121-125). / by Hugo Valle-Herrera. / M.S.

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1890. / by Geo. B. McConnell. / B.S.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1999. / Includes bibliographical references (p. 247-255). / This research developed a methodology to assess the design of complex large-scale products with respect to the performance of their production processes. In complex large-scale projects, physical and functional relationships among the product systems and components, along with concurrency and co-location of their production processes, generate inter-system process dependencies that drive the relative production rates among the systems. The methodology links the complexity of the product to the complexity of the production process at the level of detail of the single component and task to model the impacts of inter-system process dependencies on production performance. This detailed focus makes the methodology highly responsive to changes in design and technology and able to capture primary, secondary and tertiary impacts of change on production performance. Based on the methodology, a dynamic process simulation model has been developed to systematically assess different combinations of design and technology alternatives across multiple dimensions of production performance. Performance measures include project duration, costs, resource utilization and index of workers' exposure to dangerous conditions. Simulated scenario testing based on actual data from a construction project, the renovation of Baker House (MIT building W7), demonstrates that 1) inter-system process dependencies strongly influence production performance, 2) these links build their dynamic effects on production performance at the detailed task and component level, and 3) the nature of the links and their spatial and temporal location vary as changes are introduced in the design and in the production specifications. One important consequence is that the specification and optimization of the production processes for product systems and components as separate from one another leads to solutions that may be sub-optimal for the performance of the whole project. In addition, the specification and the representation of complex production processes at the aggregate level fails to capture important impacts of design and technology changes and, thus, leads to inconsistent duration and cost estimates. / by Alessandra Orsoni. / Sc.D.