Dynamic stiffnesses of foundations

A general theory that described the B.I.E.M. in steady-state elastodynamics is developed. A comprehensive formulation for homogeneous and heterogeneous media is presented and also some results in practical cases as well as a general review of several other possibilities.

Impedance of foundations using the Boundary Integral Equation Method

Dynamic soil-structure interaction has been for a long time one of the most fascinating areas for the engineering profession. The building of large alternating machines and their effects on surrounding structures as well as on their own functional behavior, provided the initial impetus; a large amount of experimental research was done,and the results of the Russian and German groups were especially worthwhile. Analytical results by Reissner and Sehkter were reexamined by Quinlan, Sung, et. al., and finally Veletsos presented the first set of reliable results. Since then, the modeling of the homogeneous, elastic halfspace as a equivalent set of springs and dashpots has become an everyday tool in soil engineering practice, especially after the appearance of the fast Fourier transportation algorithm, which makes possible the treatment of the frequency-dependent characteristics of the equivalent elements in a unified fashion with the general method of analysis of the structure. Extensions to the viscoelastic case, as well as to embedded foundations and complicated geometries, have been presented by various authors. In general, they used the finite element method with the well known problems of geometric truncations and the subsequent use of absorbing boundaries. The properties of boundary integral equation methods are, in our opinion, specially well suited to this problem, and several of the previous results have confirmed our opinion. In what follows we present the general features related to steady-state elastodynamics and a series of results showing the splendid results that the BIEM provided. Especially interesting are the outputs obtained through the use of the so-called singular elements, whose description is incorporated at the end of the paper. The reduction in time spent by the computer and the small number of elements needed to simulate realistically the global properties of the halfspace make this procedure one of the most interesting applications of the BIEM.

A Study on the liquefaction risk in seismic design of foundations

A fully coupled non-linear effective stress response finite difference (FD) model is built to survey the counter-intuitive recent findings on the reliance of pore water pressure ratio on foundation contact pressure. Two alternative design scenarios for a benchmark problem are explored and contrasted in the light of construction emission rates using the EFFC-DFI methodology. A strain-hardening effective stress plasticity model is adopted to simulate the dynamic loading. A combination of input motions, contact pressure, initial vertical total pressure and distance to foundation centreline are employed, as model variables, to further investigate the control of permanent and variable actions on the residual pore pressure ratio. The model is verified against the Ghosh and Madabhushi high acceleration field test database. The outputs of this work is aimed to improve the current computer-aided seismic foundation design that relies on ground’s packing state and consistency. The results confirm that on seismic excitation of shallow foundations, the likelihood of effective stress loss is greater in deeper depths and across free field. For the benchmark problem, adopting a shallow foundation system instead of piled foundation benefitted in a 75% less emission rate, a marked proportion of which is owed to reduced materials and haulage carbon cost.

Pora- ja puristuspaalujen kuormansiirtorakenteet

Tämä insinöörityö tehtiin Lemcon Oy:lle. Työn tavoitteena oli selvittää pora- ja puristuspaalujen yhteydessä käytettävien kuormansiirtorakenteiden toimivuutta ja ympäristövaikutuksia. Selvitystä tehtiin vertailemalla kahdessa eri tavalla toteutetussa kohteessa käytettyjä rakenneratkaisuja. Työn teoriaosaan kerättiin tarvittavat perustiedot porapaalutuksesta ja puristuspaalutuksesta. Molempien paalutusmenetelmien toteutustapoja ja käytettävää kalustoa selvitettiin yleisellä tasolla. Lisäksi tutkittiin yleisimmin käytettyjä kuormansiirtorakenteita, joiden toiminnasta laadittiin kuvaukset. Työssä ei otettu kantaa kuormansiirtorakenteiden mitoitukseen. Tutkimusosassa selvitettiin erilaisten kuormansiirtorakenteiden käytön painumavaikutuksia kahden Turussa rakennetun kohteen työnaikaisten painumien mittausten vertailun avulla. Lisäksi analysoitiin Turun vanhan pääkirjaston suurten työnaikaisten painumien syitä ja syntymekanismeja. Analyysien tuloksena todettiin, että kantavan laatan ja porapaalutuksen yhdistelmän käyttö kuormansiirtorakenteena aiheuttaa herkästi suuriakin työnaikaisia painumia. Tämä johtuu pääasiassa painumista aiheuttavien työvaiheiden suuresta määrästä ennen kuin rakennus saadaan tuettua. Vaihtoehtoisten rakenteiden käyttöä tulisikin harkita etenkin, jos kunnostettavalle rakenteelle ei sallita painumista korjaustöiden aikana. Kantavan laatan käyttö kuormansiirtorakenteena voi kuitenkin olla taloudellisesti perusteltua etenkin, jos kohteen kellariin tehdään joka tapauksessa uusi lattia.

The perception of Executives and other Employees on the answer to the Sarbanes-Oxley: case study of a subsidary of the American auto industry established in Brazil

To attend and obtain the systems and. internal controls mechanisms proposed by Sarbanes-Oxley certifications is actually a big challenge,for most of the multinational companies registered in SEC (US Securities and Exchange Commission). This work has the objective of contributing to the analysis of this methodology, not only to attend the law but to reduce cost and generate value through the strengthen of the internal control systems, turning them into animating value generation process mechanisms. So, the idea is to identify the main gaps in the theory through the literature revision and a case study in order to put a question to the main deficiencies, strong points or contributions through the evaluation of the noticed practices. Finally, we can say that a a result of the research and the analyses made in. this case, the vast majority of executives and other employees recognize the benefit that Sarbanes-Oxley Act has brought to the company searched. Also recognize that, although there is still necessity for systemic adequacy and infrastructure, it helps and reinforce reducing and controlling the risks. the system of internal controls in all areas of expertise. They approach and understand that there is the need for a change in the other employees` culture to be inserted in the day-today routine as internal controls, attention to Sarbanes-Oxley and Corporate Governance, making the control cost smaller when compared to the benefits generated.

Hydrodynamic Simulations Of Vacuum-Driven Storage Tanks

As a result of urbanization, stormwater runoff flow rates and volumes are significantly increased due to increasing impervious land cover and the decreased availability of depression storage. Storage tanks are the basic devices to efficiently control the flow rate in drainage systems during wet weather. Presented in the paper conception of vacuum-driven detention tanks allows to increase the storage capacity by usage of space above the free surface water elevation at the inlet channel. Partial vacuum storage makes possible to gain cost savings by reduction of both the horizontal area of the detention tank and necessary depth of foundations. Simulation model of vacuum-driven storage tank has been developed to estimate potential profits of its application in urban drainage system. Although SWMM5 has no direct options for vacuum tanks an existing functions (i.e. control rules) have been used to reflect its operation phases. Rainfall data used in simulations were recorded at raingage in Czestochowa during years 2010÷2012 with time interval of 10minutes. Simulation results gives overview to practical operation and maintenance cost (energy demand) of vacuum driven storage tanks depending of the ratio: vacuum-driven volume to total storage capacity. The following conclusion can be drawn from this investigations: vacuum-driven storage tanks are characterized by uncomplicated construction and control systems, thus can be applied in newly developed as well as in the existing urban drainage systems. the application of vacuum in underground detention facilities makes possible to increase of the storage capacity of existing reservoirs by usage the space above the maximum depth. Possible increase of storage capacity can achieve even a few dozen percent at relatively low investment costs. vacuum driven storage tanks can be included in existing simulation software (i.e. SWMM) using options intended for pumping stations (including control and action rules ).

The employment situation in Latin America and the Caribbean: Crisis in the labour markets and countercyclical responses

As predicted in the first bulletin, produced jointly by the Economic Commission for Latin America and the Caribbean (ECLAC) and the International Labour Organization (ILO), the impact of the economic crisis continued to be felt in Latin America and the Caribbean during the second quarter of 2009. Regional exports of goods and services contracted in response to sluggish demand on international markets, while remittances and foreign direct investment flows continued to fall, credit lost its buoyancy and the total wage bill diminished, owing mainly to job losses. As a result, the growth forecasts of many countries had to be adjusted downwards. Since the end of 2008, the countries of the region had started to implement countercyclical policies —albeit with significant differences— in an effort to use public spending to counter flagging investment and consumer-spending levels and boost aggregate demand. In this second bulletin, ECLAC and ILO show how the impact of the crisis has deepened in labour markets in the region in the first half of the year and examine existing options and the outcome of public-infrastructure and emergency employment programmes designed to mitigate the impact of the crisis on the labour market. The unemployment rate has risen in practically all countries compared with the previous year and this situation worsened further in the second quarter, when urban unemployment exceeded the rate of the corresponding period in 2008 by 1 percentage point (to stand at 8.5%, up from 7.5%), while in the first quarter, the variation was 0.6 of a percentage point. Labour indicators also point to an increase in informality, a decline in employment with social protection and a decrease in full-time employment. Labour-market trends observed in the first half-year, together with the forecast for a 1.9% decline in regional GDP in 2009, suggest that the average annual rate of urban unemployment in the region will be close to 8.5%. This forecast is slightly less pessimistic than the estimate given in the first bulletin; this is attributable to the fall in the participation rate in the first half-year to levels that are expected to remain low for the rest of the year. Without this reduction in the labour supply, due largely to the “discouragement effect”, the annual average urban unemployment rate would stand at between 8.8% and 8.9%. Thus, the open urban unemployment figure would increase by 2.5 million and if the “discouraged job-seekers” are included, then the number of additional persons not finding a niche in the urban labour market would climb to 3.2 million. In the region, as in the rest of the world, there are signs that the crisis may have reached bottom in the middle of the year. In many countries, production levels have ceased their decline and there are indications of an incipient recovery leading to cautious optimism that there may be a moderate upturn in labour markets in the fourth quarter. The pace of recovery will vary from one country to the next and is expected to be gradual at best. Even with the return to a growth path, there should be no illusion that the labour problems will immediately disappear. First, the recovery in employment is expected to lag behind the upturn in economic activity. Second, since economic growth is likely to remain moderate in the short term and well below the rates recorded between late 2003 and mid-2008, demand for labour and consequently the generation of good-quality jobs will continue to be weak. Thus, countries should not relax their efforts to defend and create decent jobs, but rather should take steps to improve the effectiveness and efficiency of available instruments. In this way, the region will be in a better position not only to confront the challenges of economic recovery, but also to strengthen the foundations for social inclusion and for advancing under more favourable conditions towards fulfilment of the Millennium Development Goals.

Determination of soil properties from standard penetration test complemented by torque measurement (SPT-T)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The cone loading test to estimate deformability moduli of a tropical soil

The Cone Loading Test (CLT) consists of the execution of a load test on the piezocone probe in conjunction with the CPT test. The CLT yields the modulus ECLT, a parameter that can be used in the estimative of foundation settlement. It is also presented here the interpretation and the process to determine ECLT values from the stress-displacement curves obtained from cone loading tests. Several CLT tests were conducted at the experimental research site of São Paulo State University, Bauru-SP-Brazil. The geotechnical profile at the studied site is a brown to bright red slightly clayey fine sand, a tropical soil common to this region which is lateritic, unsaturated and collapsible. The results of CLT tests satisfactorily represent the behavior of the investigated soil. The penetrometric modulus ECLT for each depth was calculated considering the elastic behavior in the initial linear segment of the soil stress-strain curve. The ECLT moduli obtained for the various tests were compared to moduli obtained from PMT and DMT test results performed at same studied site. The shear modulus degradation curves obtained from the CLT tests are also presented. The comparison to PMT and DMT results indicates the CLT test is a viable complementary test to the CPT in the quest for better understanding stress-strain behavior of soils. Further, the CLT test provides a graphic visualization of the degradation of the shear modulus with increasing levels of strain. As a hybrid geotechnical test, CPT+CLT can be valuable in the investigation of non-conventional collapsible soils, whose literature lack reference parameters for the prediction of settlement in the design of foundations.

Advances in the study of soil-structure interaction effects on the dynamic response of piled structures

[EN]This Ph. D. thesis presents a simple and stable procedure for the estimation of periods and dampings of pile shear buildings taking soil-structure interaction into account. The coupled-system response is obtained by using a substructuring model. A boundary element-finite element coupling formulation is used to compute impedances and kinematic interaction factors of the pile group configurations under investigation. The proposed procedure is applied to perform parametric analyses to determine the influence of the main parameters of soil-structure interaction problems on the dynamic response of the superstructure. The scope of this thesis also encompasses the study of foundations including battered piles.

Parametric analysis on bridge reinforced concrete elevated pile-cap foundations

Current design practices recommend to comply with the capacity protection principle, which pays special attention to ensuring an elastic response of the foundations under ground motion events. However, in cases such as elevated reinforced concrete (RC) pile-cap foundation typologies, this design criterion may lead to conservative designs, with excessively high construction costs. Reinforced concrete elevated pile-cap foundations is a system formed by a group of partially embedded piles connected through an aboveground stayed cap and embedded in soil. In the cases when they are subjected to ground motions, the piles suffer large bending moments that make it difficult to maintain their behavior within the elastic range of deformations. Aiming to make an in-depth analysis of the nonlinear behavior of elevated pile-cap foundations, a cyclic loading test was performed on a concrete 2x3 pile configuration specimen of elevated pile-cap foundation. Two results of this test, the failure mechanism and the ductile behavior, were used for the calibration of a numerical model built in OpenSees framework, by using a pushover analysis. The calibration of the numerical model enabled an in-depth study of the seismic nonlinear response of this kind of foundations. A parametric analysis was carried for this purpose, aiming to study how sensitive RC elevated pile-cap foundations are, when subjected to variations in the diameter of piles, reinforcement ratios, external loads, soil density or multilayer configurations. This analysis provided a set of ductility factors that can be used as a reference for design practices and which correspond to each of the cases analyzed.

A summary of remarks made by William C. Lane, Librarian of Harvard University, published in the Proceedings of the Massachusetts Historical Society, December 1909

Lane addressed the Massachusetts Historical Society about the recent discovery of foundations walls, likely from Goffe College, made during the Boston Elevated Railway's excavations in Harvard Square for the subway on Massachusetts Avenue.

Projecto de execução de uma obra de arte

Trabalho de Projecto para obtenção do grau de Mestre em Engenharia na Área de Especialização em Estruturas

Sistema de fundações para postes de catenária com betão com pré-colocação de agregados (PAC)

Trabalho de Projecto de natureza científica para obtenção do grau de Mestre em Engenharia Civil