Showing papers on "Foundation (engineering) published in 2017"

Predicting Safety Risks in Deep Foundation Pits in Subway Infrastructure Projects: Support Vector Machine Approach

Abstract: Accurately predicting risks during the construction of deep foundation pits is pivotal to ensuring the safety of the workforce of public and adjacent structures. Existing methods for assess...

Hot gas around SN 1998bw: Inferring the progenitor from its environment

Abstract: Sofja Kovalevskaja Award from the Alexander von Humboldt Foundation of Germany US National Science Foundation AST-1311862

3D Numerical Model for Piled Raft Foundation

Abstract: Load sharing of piled raft foundations is known as an economical design for deep foundations. Nevertheless, research in this area has been lagging because of the complexity of the problem and lack of field data. Numerical modeling can be used to provide valuable data with a high level of success. A three-dimensional finite-element model of a piled raft foundation was developed to simulate the case of a piled raft foundation. The model accounts for pile-to-pile, raft-to-pile, pile-to-soil, and raft-to-soil interactions. The model was used to examine the effect of the key parameters governing the performance of this foundation during loading and, accordingly, the load shared by the piles and the raft. After validating the numerical model with available data in the literature, the model was used to develop data for a wide range of parameters and to examine the role of the foundation geometry, including pile spacing in the group, pile length, pile shape, pile diameter, and raft thickness. Furthermore,...

Lithospheric structure of Iberia and Morocco using finite-frequency Rayleigh wave tomography from earthquakes and seismic ambient noise

Abstract: This research was funded by the U.S. National Science Foundation EAR- 0808939. The deployment of the IberArray broadband seismic network is part of the CONSOLIDER-Ingenio 2010 TOPO-IBERIA (CSD2006-00041: Geosciences in Iberia: Integrated studies on Topography and 4-D Evolution) grant from the Spanish Ministry of Science and Innovation. Additional funding was provided by the Spanish ministry under grants CGL2010-17280, CGL2006-01171,CGL2009-09727, and CGL2007-63889,and by Generalitat de Catalunya under grant 2009 SGR 6.

The mechanistic basis for storage-dependent age distributions of water discharged from an experimental hillslope

Abstract: National Science Foundation [EAR-1344552, EAR-1344664]; Philecology Foundation; CUAHSI Pathfinder Fellowship; Science Without Borders Program; CAPES Foundation, Brazil

Study on Subgrade Settlement Characteristics After Widening Project of Highway Built on Weak Foundation

Abstract: Generally, the maximum differential settlement appears at the overlapping area of existing and new road pavement after highway widening project. However, lots of longitudinal cracks and other kinds of distresses were found on the existing pavement after the widening project of Guangsan Highway. The field investigation was carried out to find out the reason that the large settlement appeared on existing lanes induced by the weak foundation under the existing lanes, which leaded the cracks observed on the existing pavement. In addition, numerical method was adopted to verify this explanation. The parameter sensitivities were studied to discuss the characteristics of subgrade settlement after the highway widening project. Factors considered include different layouts of cement-fly ash-gravel (CFG) piles, different strengths of CFG piles and different filling materials of new embankment. The results showed that the settlement of pavement became larger when the existing road has weaker foundation. The maximum settlement on the ground surface shifts toward the new embankment when the foundation of existing road has higher strength. The lightweight filling material was proved to have advantage in reducing the settlement of the existing embankment.

Characterizing the In-Plane Rocking Response of Masonry Walls with Unbonded Posttensioning

Abstract: Unlike the use of bonded reinforcement to anchor a masonry wall to its foundation, the use of unbonded posttensioning may result in a controlled rocking response of the wall. Considering th...

Soil–structure interaction in a combined pile–raft foundation – a case study

Abstract: The present work explains the use of a piled-raft foundation in a raw materials storage building in South Ba Rịa–Vũng Tau Province of Vietnam. The proposed foundation comprises an 81 m by 55·5 m raft that connects 581 precast hollow concrete piles 20 m long with 400 mm outer diameter. The proposal takes into consideration a specific in situ soil profile and a loading scenario. After the effectiveness of a single bay of the foundation had been checked, the entire foundation system was modelled using finite-element-based geotechnical software to enable a detailed soil–structure interaction analysis. Field pile load test data were used to validate the finite-element model. Various loading conditions, such as all compartments full to all compartments empty, were considered in the analysis. The results of the analyses indicate the importance of the raft in sharing 23–31% of the total vertical load. The results obtained – such as vertical settlement, differential settlement, tilt in the raft and axial load in t...

How Firm a Foundation: "The Methodist Building" and Constructions of Public Protestantism, 1916-1936

Abstract: This dissertation examines the history of the Methodist Building in Washington, D.C., in order to understand how the building exhibited aspirations for public Protestantism during the Prohibition era. Over four chronological chapters, this dissertation examines how the Methodist Building was a contested site, revealing the tensions of race, nation, religion, and politics in twentieth-century American Methodist identity. The project focuses on how the Board of Temperance, Prohibition, and Public Morals of the Methodist Episcopal Church wanted to construct the Methodist Building to announce the national ambitions of Methodism and counter perceived influences of Catholicism in Washington; how the Board employed material culture and public ceremonies to position the new Methodist Building as a platform for public Protestantism that would reform the nation; how the public Protestantism that the Board sought to embody in the Methodist Building sparked a debate over whether it was a lobby; and the campaign to make the Methodist Building the headquarters of the new national Methodist Church once the Northern and Southern branches reunited in 1939. Close examination of the Methodist Building illustrates how the Board used the building to argue for the moral and cultural authority of Methodism and Protestantism in society, and how others challenged that public role. This study of the Methodist Building invites a reconsideration of the early twentiethcentury era of Methodist and mainline Protestant institution building. This thematic research challenges the view that Methodist institution building during this period was an afterthought or even a declension to the nineteenth-century revivals and itinerant preaching. A deeper appreciation of the institutions and physical structures Methodists built during the early twentieth century helps to explain how this religious tradition transitioned from a revivalist movement into

Category Theory as a Formal Mathematical Foundation for Model-Based Systems Engineering

Abstract: In this paper, we introduce Category Theory as a formal found ation for model-based systems engineering. A generalised view of the system based on category theory is presented, whe re any system can be considered as a category. The objects of t he category represent all the elements and components of the system and t he arrows represent the relations between these components (objects). The relationship between these objects are the arrows or the morphisms in the category. The Olog is introduced as a formal language to describe a given real-world situation description and requ ir ment writing. A simple example is provided.

The Deep Mixing Method: Bearing Capacity Studies

Abstract: Nowadays, several techniques are employed to improve the problem of carrying out construction in soft soils by increasing the strength of the soil foundation and reducing the settlement of the soil. Among these stabilizing techniques, the deep mixing method is regarded as the most popular. The deep mixing method is a soil modification method where the soil is mixed in situ with stabilizing agents, commonly soil–cement columns. It increases the strength of the soil, providing bearing resistance and improved settlement performance. Deep mixing is carried out in situ using a machine equipped with mixing blades mounted at the end of a tube that has a nozzle at the lower end. The stabilizer agent is injected into the soil via the nozzle using a pumping system so that it mixes with the soil as the blades are rotated. Throughout this paper, previous works by numerous researchers on deep mixing including laboratory work, full-scale field tests, analytical and numerical analyses related to bearing capacity are reviewed. The techniques and results used are discussed with the help of figures depicting charts, failure modes, and the model configuration setup. It was found that the deep mixing method is suitable for use with any type of soil and provides a better alternative to the existing method of improving soft clay ground, especially with regard to the soil bearing capacity. In addition, future research is needed to improve the use of the method for soil improvement in the construction industry.

Experimentally manipulating the landscape of fear to manage problem animals

Abstract: We thank A. M. Clemo and H. J. Chalmers of Raptor Force for allowing us to observe their falconry activities. We thank F. M. Fazey, F. S. Morling, and S. K. Abdu for their field assistance. We thank the golf course managers for access to the courses and support throughout the study, in particular W. A. Hill. Funding for the project was received from the Department of Science and Technology-National Research Foundation (DST-NRF) Centre of Excellence fund, University of Cape Town.

Lateral capacity assessment of offshore wind suction bucket foundation in clay via centrifuge modelling

Abstract: The lateral bearing behaviors of suction bucket foundations for offshore wind turbines are investigated by centrifuge modelling in this paper. The centrifuge tests were performed in lightly over-consolidated clay and heavily over-consolidated clay, and three bucket foundation models with aspect ratios of 0.38, 0.5, and 1.3 were tested. The tests were force-controlled, and both static loads and cyclic loads were applied. In static tests, ultimate bearing capacities of suction bucket foundations were extracted from load-displacement curves as the first method, and the results were reinforced by stiffness-displacement curves. The displacement rates were calculated to find critical bearing capacities and ultimate bearing capacities of the foundations as the second method. The cyclic tests include cyclic loads with uniform and increased amplitudes. The accumulated lateral displacements and secant stiffnesses were discussed, and their variations with cycle numbers were studied.

Analysis of bacterial communities in and on concrete

Abstract: Bacteria are known to catalyze degradation of concrete, and have more recently been used to repair micro-cracks in or form protective biofilms on cement mortar. However, the microbial communities in and on concrete under ordinary weathering conditions have not been characterized, in part because of difficulty in extracting DNA from inside concrete specimens. Here, we report a method for extraction of nucleic acids directly from hardened concrete. Using this method and classical cultivation methods, we demonstrate that most bacteria in or on concrete belong to two taxonomic groups, that the bacterial diversity is similar on the concrete surface and in the interior, and that many bacteria in and on concrete are related to microbes found in other dry, saline, or alkaline environments. This method lays the foundation for the creation of bioindicators for concrete and may open new avenues for the fields of non-destructive evaluation and assessment of concrete structures.

Superstructure–foundation interaction in multi-objective pile group optimization considering settlement response

Abstract: The full potential of pile optimization has not been realized as the interactions between superstructures and foundations, and the relationships between material usage and foundation performance ar...