Foundation Wall Research Articles

Numerical Simulation Analysis of Soil Nailing Wall Based on FLAC during the Excavation of the Foundation Pit

On the basis of a typical engineering, a foundation of soil nailing walls supporting simulation model of soil nailing on the structure of the excavation is established with FLAC, the construction process of the supporting structure is analyzed in the dynamic simulation. The deformation characteristics of the supporting structure are analyzed during the construction process, the law of the supporting body deformation with the difference of excavation steps is summarized. The situ test data of the deep foundation horizontal displacement and vertical displacement are obtained by testing in situ. Some useful conclusions are summarized by comparative analyzing the numerical simulation value and situ test data, providing guidance for the design and construction of the pit soil nailing wall.

Analytical quantification of airflows from soil through building substructures

Soil gas pollutants (VOCs, radon, …) have long been known to intrude into buildings through various openings, e.g., cracks and gaps in the foundations. As yet no model has been developed which can quantify this rate of flow whilst taking into account various substructure configurations. This is due to the complex phenomena that need to be consider and particularly to the difficulty in estimating pollutant flows at soil-building interfaces. In this paper analytical models have been developed to quantify these flows. The models have been developed for some typical substructure configurations: slab-on-grade, basement and crawlspace. The inputs of these models include particularly the foundation wall depth and the slab permeability. The analytical models have been compared to existing analytical models for one of the configurations. Moreover a 2-D finite element model has been used for numerical comparison. The models are presented as pressure-flow relationships and can be integrated into risk assessment tools in order to study the impact of soil gas pollutants on indoor air quality.

Damage-Control Systems Using Replaceable Energy-Dissipating Steel Fuses for Cold-Formed Steel Structures: Seismic Behavior by Shake Table Tests

AbstractA system that controls the rocking behavior of multistory shear walls is proposed as an innovative damage-control system for cold-formed steel structures. In this system, we have developed a new hold-down equipped with a fuse function (HDF) that controls the rocking behavior and is placed on the foundation of multistory shear walls. The HDF contributes to reducing damage to both structural and nonstructural members in cold-formed steel framed buildings, dissipating seismic input energy in the event of a large earthquake. The present paper describes the shake table tests performed using one-story, one-span, real-size specimens to investigate the fundamental behavior of the developed system. By using shake table tests in which the type of hold-down and the magnitude of input ground motion were varied as parameters, it was clarified that the plasticization of HDFs could reduce the base shear of specimens and that the energy dissipation by the HDFs could subdue the uplift deformation of the specimens....

Prioritizing Method for Retrofitting Toronto’s Single-Family Housing Stock to Reduce Heating and Cooling Loads

AbstractThis study analyzes simulated secondary (site) energy consumption before and after applying a series of building envelope retrofits to inform a prioritized list of retrofit options tailored to one of four single-family dwelling styles in Toronto, Ontario, Canada. Four archetype homes were developed to represent Toronto’s existing urban housing stock: (1) 2-story century home; (2) wartime bungalow; (3) 1970s Ontario Building Code 2-story home; and a (4) 2-story modern house. Base case geometry and inputs were developed from a variety of sources, including a Canadian national database and modeled using the HOT2000 software package. The prioritized retrofit strategy worked toward achieving a target secondary energy intensity of 100 kW⋅h/m2 and included increasing insulation levels in the main walls, foundation walls, slab, and ceiling, replacing windows and doors, and air sealing to various degrees. Results showed the retrofit strategies affected each archetype differently, leading to the conclusion ...

Research on the Rehabilitation of the Ancient City Wall of the Wuchang Uprising Gate

To commemorate the 100th anniversary of the Xinghai Revolution, the government of Wuchang district in Wuhan City intends to rehabilitate rain-wind corridor, feudal pavilion and the city walls. After access to historical data, site survey, mapping, photographing and measuring, the rehabilitating engineering program of rain-wind corridor, feudal pavilion and the city walls of the Wuchang Uprising Gate is achieved. In the fourth year of Hongwu (1371), Ming dynasty, Zhou Dexing, the duke of Jiangxia, built Wuchang city on the basis of Yingzhou city of Tang dynasty. Wuchang city has large scale. In Ming and Qing dynasty, it was the legacy of county, town, city and province. Its diameter from the east to the west was of 2.5 km, with 3 km from the north to south. The thickness of wall foundation is 22.44 m, with top thickness 17.82 m. Nine gates were designed for the ancient city. The Uprising gate, one of the nine gate of the Wuchang ancient city, was opened to the south and also the busiest gate for entering the city. New Army Engineering Battalion of Hubei took the lead and fired the first shot. And then they occupied Zhonghe Gate and Chu Wangtai to welcome the South Lake artillery, Ma team and other revolutionaries.

Effect of Fipronil on Subterranean Termite Colonies (Isoptera: Rhinotermitidae) in the Field

To assess possible colony-level effects of fipronil, a commonly used nonrepellent termiticide, we conducted a field study of eight houses in the Raleigh, NC, area with infestations of the eastern subterranean termite Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae). We installed an extensive grid of in-ground monitoring stations on each property (mean = 68.6 monitors per property) and collected samples from these stations as well as from mud tubes in the structure and wood debris in the yard for approximately 6 mo. We genotyped all samples by using microsatellite markers to identify the number and locations of colonies present on each property. Houses were treated with either a full treatment (n = 5) or exterior/localized interior treatment (n = 3). After treatment, the monitors were checked monthly for 3 mo and then quarterly for 3 yr to track the fate of colonies. Wood debris in natural areas was checked semiannually for 3 yr. All 11 of the treated colonies (those attacking structures) disappeared within 90 d of treatment and were not found again. These colonies were presumed to be eliminated. In contrast, 60% of untreated colonies (those located > 6 m from the foundation wall at the time of treatment) continued to persist throughout the study, as did 25% of the likely treated colonies (those occupying monitors 0.5 m from the foundation wall where the treatment was applied). Our results provide strong evidence for potent colony wide effects of fipronil on subterranean termites leading to colony suppression and likely colony elimination under field conditions.

Numerical analysis of bearing reinforcement earth (BRE) wall

This paper presents a numerical simulation of the bearing reinforcement earth wall by PLAXIS 2D. The bearing reinforcement was regarded as a cost-effective earth reinforcement. The model parameters for the simulation were obtained from the conventional laboratory tests and back analyses from the laboratory pullout tests of the bearing reinforcement. The simplified method for modeling the bearing reinforcement, which converts the contribution of friction and bearing resistance to the equivalent friction resistance, is introduced. This method is considered to be acceptable and practical in working state with sufficient factor of safety and small pullout displacement. The bearing reinforcement is modeled as the geotextile and the equivalent friction resistance is represented by the soil/reinforcement interface parameter, R, which was obtained from a back analysis of the laboratory pullout test results. The R values are 0.65 and 0.75 for the bearing reinforcement with 2 and 3 transverse members, respectively. The change in bearing stresses, settlements, lateral earth pressures and tensions in the reinforcements during and after construction is simulated. Overall, the simulated test results are in good agreement with the measured ones. The simulated results show that the BRE wall behaves as a rigid body, retaining the unreinforced backfill. The simulated bearing stress presents a trapezoid distribution shape as generally assumed by the conventional method of examination of the external stability of MSE walls. The simulated settlement is almost uniform due to a high stiffness of the rigid foundation and the bearing reinforcements. The maximum lateral movement occurs at about the mid-height of the wall, resulting in the bi-linear maximum tension plane. The knowledge gained from this study can be applied to other BRE walls with different wall heights, foundations and features of bearing reinforcements.

Analysis of Direct Budget Implementation Building Construction Work

The study entitled Analysis of Direct Budget Implementation Building Construction Work aims to compare the direct costs of implementation of the work in the field with the cost of the contract. Because of differences in costs in the field with the cost of the contract, it can affect the size of the benefits obtained from the executor. Which is the object in this paper is the allocation of direct costs for materials, wages and equipment. To support the calculation of the data required at the time of implementation, which consists of primary data and secondary data, the scope of work is reviewed in this study is the work of the foundation, plinth, columns and walls. Observation of the direct costs of research and calculation begins at the time of entry, use, and installation of materials and labor used much every day. While the calculation of the budget in the contract for the cost of resources is calculated by using analysis of BOW. From the calculation results obtained by the direct costs of implementation for the scope of work to be a review is Rp.211,771,639 while the amount of the contract budget is Rp.320, 342.678 to the difference in cost is Rp.108,571,039 or 33.89%. In a project cost of use is strongly influenced by the use and management of resources by both skilled in the art to manage any resources used. At the implementation stage will be the cost difference between the costs of implementing to contract cost. These differences greatly affect the size of the profit earned by the executor, and then the problem that arises is how to calculate and analyze the cost of the contract with the implementation of cost in the field. To find out the direct costs that occurred in the implementation of the work done by direct observation in the field, from which the data obtained about the amount of material, number / type of employment and type of equipment used at the time of execution, while the budget for the contract, for the cost of resources is calculated analysis using BOW. Objectives to be achieved in this paper are to compare the direct costs of implementation of the work in the field at a cost that is in the contract. The data used to calculate the direct costs consist of primary data is data obtained from direct observation in the field. The primary data consists of data obtained materials, equipment data, employment data and time data based on the implementation of workforce skills. Other data used are secondary data is data obtained from executor the project. The scope of work to be reviewed at the building project is just a limit on the foundation work, plinth, columns, and walls to look for the calculation of the direct costs of implementation.The results of this study is expected to be useful as an information and reference for decision makers in the planning and budget as a guideline to create a method of execution in the perform and determine the resource settings at the time of implementation in the future.

Early Historic settlement beneath the Grassmarket in Edinburgh

Archaeologically monitored excavations in the Grassmarket, Edinburgh uncovered diverse remains dating from prehistory to the First World War. The stratigraphic sequence included pits created in the middle of the Bronze Age, Early Historic features and deposits, a series of medieval surfaces, a section of the Flodden Wall and post-medieval building foundations. The Early Historic features provide rare evidence for Edinburgh’s development prior to the 12th century and form the focus of this article.
 Several features, created during the Anglian occupation of the Lothians, suggest the presence of a settlement between the late 6th and early 10th centuries AD, overlooked and possibly servicing a high status site on Castle Rock. The evidence is compared to archaeological results from other settlements formerly within the Anglian kingdom of Bernicia (Northumbria).
 Deposits over a structure were radiocarbon dated to the 11th–12th century, when the region was under Scottish control. Associated environmental remains and leather offcuts indicated the holding, butchering and processing of livestock. This evidence pre-dates the documented use of the area as a medieval market and is interpreted as relating to a pre-burghal phase of use.
 The significance of the results in terms of our understanding of Edinburgh’s development, and to assessments of archaeological potential in Scottish medieval towns in general, is also discussed.

Applications of hybrid genetic algorithms in seismic tomography

Abstract Almost all earth sciences inverse problems are nonlinear and involve a large number of unknown parameters, making the application of analytical inversion methods quite restrictive. In practice, most analytical methods are local in nature and rely on a linearized form of the problem equations, adopting an iterative procedure which typically employs partial derivatives in order to optimize the starting (initial) model by minimizing a misfit (penalty) function. Unfortunately, especially for highly non-linear cases, the final model strongly depends on the initial model, hence it is prone to solution-entrapment in local minima of the misfit function, while the derivative calculation is often computationally inefficient and creates instabilities when numerical approximations are used. An alternative is to employ global techniques which do not rely on partial derivatives, are independent of the misfit form and are computationally robust. Such methods employ pseudo-randomly generated models (sampling an appropriately selected section of the model space) which are assessed in terms of their data-fit. A typical example is the class of methods known as genetic algorithms (GA), which achieves the aforementioned approximation through model representation and manipulations, and has attracted the attention of the earth sciences community during the last decade, with several applications already presented for several geophysical problems. In this paper, we examine the efficiency of the combination of the typical regularized least-squares and genetic methods for a typical seismic tomography problem. The proposed approach combines a local (LOM) and a global (GOM) optimization method, in an attempt to overcome the limitations of each individual approach, such as local minima and slow convergence, respectively. The potential of both optimization methods is tested and compared, both independently and jointly, using the several test models and synthetic refraction travel-time date sets that employ the same experimental geometry, wavelength and geometrical characteristics of the model anomalies. Moreover, real data from a crosswell tomographic project for the subsurface mapping of an ancient wall foundation are used for testing the efficiency of the proposed algorithm. The results show that the combined use of both methods can exploit the benefits of each approach, leading to improved final models and producing realistic velocity models, without significantly increasing the required computation time.

The Petrographical-Geochemical Properties and Industrial Availability of the Karadeniz Eregli Andesites (Zonguldak)

Aim of this study is to determine the geological properties (lithology, petrography, geochemistry) and industrial usibility of the Upper Cretaceous volcanics, seperated on the area, among Kozlu-Krd. Eregli and Ormanli, westside of Zonguldak. Volcanics, described as andesite, basaltic andesite and trachy-andesite by petrographically and geochemically, have subduction zone calk-alkaline character. Firstly, in laboratuary studies the aggregate tests (grading, specific gravity, water absorption, organic impurity, flakiness index, Los Angeles test for resistance to wear, peeling test, freezing resistance and UCS were realized on the 5 selected fresh patterns, match with the standarts (TS, ASTM, AASHO). Secondly, concrete tests (grading of the concrete aggregates, concrete preperation, slump test, specific density of concrete and UCS of the concrete) were made on the concrete patterns with volcanic aggregate additive.Statistical relationships were determined between values of the agreggate and concrete tests results. Both petrographical, chemical, physical and mechanical tests values of the agreggates and concretes are also match with the standarts, given above.As a conclusion, realized that volcanic aggregates for superstructure materials and C 25/30 concrete which made with volcanic aggregate (by using the specimen of N-4 aggregate) for rainforcement buildings, bridges, foundation walls can be used.

Radon prevention in new construction in Finland: a nationwide sample survey in 2009

The building code for radon prevention and the associated practical guidelines were revised in Finland in 2003-2004. Thereafter, preventive measures have become more common and effective and indoor radon concentrations have been markedly reduced. In this study, the indoor radon concentration was measured in 1500 new low-rise residential houses. The houses were randomly selected and represented 7 % of the houses that received building permission in 2006. The average radon concentration of all the houses measured, which were completed in 2006-2008, was 95 Bq m(-3), the median being 58 Bq m(-3). The average was 33 % lower than in houses completed in 2000-2005. The decrease was 47 % in provinces with the highest indoor radon concentration and 26 % elsewhere in the country. In houses with a slab-on-ground foundation that had both passive radon piping and sealing measures carried out using a strip of bitumen felt in the joint between the foundation wall and floor slab, the radon concentration was on average reduced by 57 % compared with houses with no preventive measures. Preventive measures were taken nationwide in 54 % of detached houses and in provinces with the highest radon concentration in 92 % of houses.

Residential energy efficiency programs, retrofit choices and greenhouse gas emissions savings: a decade of energy efficiency improvements in Waterloo Region, Canada

SUMMARY Since 1999, the Residential Energy Efficiency Project, through Green Communities Canada, has been a delivery agent for EnerGuide for Houses and ecoENERGY programs in the Waterloo Region. This research analyzed 10,208 initial and 2,383 final evaluations made by the Residential Energy Efficiency Project between May 1999 and February 2009 to understand what energy efficiency improvements homeowners have made over time. Because of changes to federal and provincial programs, the data are analyzed under four main periods: the EnerGuide program with no financial incentives (1999 to 2003), the EnerGuide program with financial incentives based on performance (2003 to April 2006), no official program (April 2006 to April 2007), and the ecoENERGY program with financial incentives by measure (April 2007 to February 2009). Participating households were divided into cohorts associated with each of these periods. For each of these cohorts, the impact of retrofit changes was assessed as the amount of energy and greenhouse gas emissions saved. It was also assessed whether homeowners treated the ‘house as a system’, that is, whether they made multiple energy efficiency changes (e.g., increasing insulation in the ceiling, foundation or main walls, upgrading windows and doors, air sealing, improving heating, ventilation, air conditioning, or domestic water heating systems) or focused on a single change associated with large energy savings, such as changing their furnace. The findings show that recommended and achieved energy and greenhouse gas emissions savings differed across cohorts, and that achieved savings were generally less than recommended. The final cohort of homeowners who achieved major energy savings was twice as likely (25%) to take the single action of replacing the furnace as during earlier periods. Changes to furnaces were associated with higher levels of energy savings, but overall, 85% of the homes which achieved the highest levels of savings made multiple changes, thereby adopting the ‘house as a system’ approach to energy efficiency improvements. Finally, homeowners were less likely to make improvements to the building envelope, and these improvements were generally less extensive than the identified technical potential for improvement. Copyright © 2011 John Wiley & Sons, Ltd.

Aquisgrani terrae motus factus est (part 1): The Aachen cathedral (Germany) built on weak ground?

Charlemagne (Charles the Great) placed the centre of his kingdom during Carolingian times in Aachen, Germany (Aquisgrana). This medieval period and his regency are associated with a period of extensive constructions in Aachen, including the Carolingian part of the Aachen cathedral. The cathedral was the first building in Germany to join the UNESCO World Heritage list. The foundations and construction ground of the cathedral were excavated during recent archaeological and geotechnical investigations. The cathedral is founded on pillars and piles in Devonian blue limestone and shale, covered by Pleistocene loess sediments. Remains of Roman buildings, such as thermae, are situated below this part of the cathedral. The pillars are connected by up to 5 m deep foundation walls and are up to 2.4 m thick. Even though information about the construction site is important for the assessment of structural health and remediation measures, it is often rare for old historical buildings. Documentations from construction time concentrate on the construction progress and financial aspects. Detailed descriptions on the foundation ground and techniques are usually not preserved. This information is of relevance for assessment of earthquake related structural damages and site effects on construction. Investigations in the course of remediation measures or archaeological surveys fill this information gap. They provide insights in the ancient foundation techniques and can be used for identifying earthquake related phenomena in the construction site. Furthermore, a direct insight into potential seismic effects associated with the ground and building response on seismic shaking becomes possible. In the case of the Aachen cathedral, typical geotechnical investigation methods including drilling and laboratory tests were applied together with GPR measurements to evaluate the construction ground and evaluate potential seismological effects.

The Finite Element Analysis on Foundation Supported with Composite Soil Nailing

This article adopts the general finite element analysis software——ANSYS to do the numerical analysis and research on some Composite Soil Nailing. The Drucker-Prager model modified with depth was adopted as the constitutive model. The article presents a lot of numerical calculations and analysis, researching the effects of excavation order, nailing length and nailing obliquity to the horizontal displacement of foundation wall, surface sedimentation and rise of the foundation bottom, giving some useful conclusion which can be used as the references to the design and construction of foundation supported with Composite Soil Nailing.

Contribution to a round church reconstructed from its foundation wall

In the Carpathian-basin many of the early-medieval church types were the rotundas, but the majority of these churches have not survived in their original form. Most of these churches were modified into larger churches, or were destroyed during the Ottoman invasion. In this paper, it is proved, that the rotundas in the Carpathian-basin are not the result of adoption. Their large numbers, described by their small sizes and special forms, supports this supposition. This paper covers the reconstruction work of a rotunda in the mountains of Gerecse. During excavation, not only the hewn stones of the foundation walling were found but other findings come to light as well. The reconstruction plan of the church was assisted by these findings and also by data of other similar churches survived in their original form. The church was reconstructed not far from the place of the excavation using contemporary technology. The reconstruction of the church is the center part of this work, but we will also talk briefly about the process of implementation and the technology of the age as well.

Thermal analysis of above-grade wall assembly with low emissivity materials and furred airspace

A 3D numerical model was developed to investigate the effect of foil emissivity on the effective thermal resistance of an above-grade wall assembly with foil bonded to wood fibreboard in a furred assembly having airspace next to the foil. This model solved simultaneously the energy equation in the various material layers, the surface-to-surface radiation equation in the furred airspace assembly, Navier–Stokes equation for the airspace, and Darcy and the Brinkman equations for the porous material layers. In this work, the furring was installed horizontally. In the first phase, the present model was benchmarked against the experimental data generated by a commercial laboratory for an above-grade wall assembly. The wall consists of a conventional wood frame structure sheathed with fibreboard and covered on the interior side with a low emissivity material bonded to wood fibreboard that is adjacent to a furred airspace assembly. The results showed that the predicted R-value was in good agreement with the measured one. After gaining confidence in the present model, it was used to predict the effective thermal resistance of the same above-mentioned wall but having Oriented Strand Board (OSB) sheathing in lieu of wood fibreboard sheathing. In the second phase, the model was used to quantify the contribution on the wall R-value by having a low foil emissivity. The results showed that a low foil emissivity of 0.04 can increase the R-value of this wall to as much as ∼9%. This is on-going research. The present model is being used to investigate the transient thermal response of foundation wall systems with furring installed horizontally and vertically, and subjected to different Canadian climate conditions.

Using surface and cross-hole resistivity tomography in an urban environment: An example of imaging the foundations of the ancient wall in Thessaloniki, North Greece

This work describes the application of the electrical resistivity tomography (ERT) technique, in both surface and cross-hole modes, for subsurface exploration in an urban environment. The objective was to image the foundations of the Thessaloniki city walls (Region of Macedonia, North Greece) at locations that will be affected by the construction of a new underground Metro line. The surface ERT survey was performed along lines crossing directly over the wall on areas where it had partly collapsed. ERT surveys were also applied at places where the main over ground structure of the walls had been completely destroyed and what is left now is primarily only the ancient subsurface foundations. In addition, the present day ground surface is partially covered by concrete pavement slabs. In both cases, nonconventional electrodes were partially used to carry out a number of ERTs on the ground surface. This was necessary in order not to destroy the pavement slabs and most importantly not to damage in any way the monuments. An example of cross-hole ERT is also presented. Cross-hole ERTs were conducted because detailed measurements employing surface ERT were not possible due to limitations imposed by the urban environment. The way that the boreholes were instrumented is also presented. The combined surface and borehole tomographies produced images of the buried structures allowing the assessment of their geometrical shape and of the dimensions of the foundations of the ancient wall.

Using Insulation in China’s Buildings: Potential for Significant Energy Savings and Carbon Emission Reductions

Most old residential and commercial buildings in China are not insulated or not to new standards. This is true even in regions with very cold winters or regions with very hot summers. The insulation in new buildings is very poor relative to North American standards. However, insulating the exterior walls, attic roofs, and foundation walls to new standards of buildings in China would reduce the need for heating and air conditioning, and thus would save roughly 200 million tons of coal each year. This in turn would lead to a reduction in CO2 emissions of about 510 million tons per year, which is equal to about 8.4% of China’s total carbon emissions in 2006. The use of insulation in buildings will help homeowners save money, help China save energy and help the environment all at the same time. Insulation will provide a continued payback to the homeowner, not only in dollars and cents, but also by providing a more enjoyable and comfortable living environment for many years.

Comparison of accelerated climate ageing methods of polymer building materials by attenuated total reflectance Fourier transform infrared radiation spectroscopy

The degradation of the polymer building materials polypropylene (PP) and high density polyethylene (HDPE) intended for application as water barriers/repellants around building foundation walls have been studied. The PP and HDPE samples have been subjected to various accelerated climate ageing methods for comparison, including exposure to ultraviolet and infrared radiation, heated air, water spray and freezing. The climate ageing processes have been qualitatively and quantitatively investigated by attenuated total reflectance (ATR) Fourier transform infrared (FTIR) radiation spectroscopy.