Base Of Wall Research Articles

Strength- and Moisture-Related Studies of Historical Building Materials: A Case Study from Southern Estonia

Demolition of existing buildings turns building products into waste. The amount of demolition waste is increasing globally. The current case study is an example of fulfilling the EU Waste Framework Directive of reducing demolition waste by reuse of historical materials in their original structures. The aim of this paper is to investigate construction materials from 19th and 20th centuries and their mechanical and physical properties in a case study building from the conservation area of Võru city, South Estonia. Timber structures of the case study building were non-destructively tested on-site using a resistive method. Ceramic brick plinth and basement walls, as well as concrete and granite ceiling, were tested in situ non-destructively (rebound hammer test) for compressive strength estimation. Previously dismantled timber logs, slats and ceramic bricks were tested in the laboratory for compression and bending, respectively. The logs and slats matched the European timber bending strength classes C22 and C40, respectively. The compressive strength of the studied ceramic bricks was comparable to that of newly produced bricks. The non-destructive moisture content of timber structures varied in spring (5–20%) but was steady in the autumn (5–7%) tests. The rebound hammer test overestimated by 1.5…2 times the compressive strength of the studied materials compared to laboratory tests.

Effect of soil-building interaction on dynamic earth pressure on basement walls

This study investigates dynamic earth pressure on basement walls by considering soil-structure interaction, a factor that is often overlooked by conventional methods like Mononobe-Okabe, Seed and Whitman, and Wood. Superstructure, basement, and soil were numerically simulated in a single model to evaluate the inertial and kinematic effects of buildings on dynamic earth pressure on the basement walls. The numerical model was validated using data from a centrifuge test and an instrumented building. Then, a parametric study was performed, with the height, width, and basement depth of the building varied with six input motions. The results showed that the inertia of the building increased dynamic thrust. Furthermore, the dynamic thrust showed a similar trend with the displacement response spectrum curve of the ground surface acceleration as the building height increased, while the distribution shape transitioned from triangular to inverted triangular. Additionally, wider buildings had increased dynamic earth pressure, while deeper buildings exhibited smaller normalized dynamic thrust.

Study of the use of wallpaper to mitigate radon exhalation from building materials in indoor spaces

Radon gas is known to exhale from the ground and can enter and accumulate inside buildings. Many countries set radon limit concentrations and propose mitigation techniques applied in the outdoors to prevent radon from entering buildings. However, radon can also exhale from building materials, e.g. cement, bricks, marble or tiles, contributing high concentrations indoors. Space ventilation is the most used technique to reduce the indoor radon concentration to safe limits, but sometimes, it is not enough. In these cases, it is necessary to apply alternative techniques. This work exposes a prevention technique to reduce radon concentration in indoor spaces that come from building materials or from the subsoil diffusing through basement walls, based on the use of wallpapers. The use of wallpapers is a common decorative technique in homes and buildings, which is compatible with interior finishes and is simple to apply, easily accessible, commercially available and inexpensive. Different commercial wallpapers were selected with a cellulosic and polymeric base and vinylic, cellulosic, latex or non-woven coating material. Configurations of single and double layers of wallpaper and a triple configuration by adding an intermediate layer of aluminium film have been tested. Tests to determine the reduction of radon concentration were performed, and diffusion coefficient and diffusion length were calculated following an adaptation of ISO/TS 11665–13 standard. Radon reduction of 90%, low-medium radon resistance and a diffusion coefficient around 10−11 m2/s were reached for single-layer configuration, and up to 98% of radon reduction, medium radon resistance and diffusion coefficient of 10−12 m2/s with double-layer configuration for dense non-porous base wallpapers with vinylic and non-woven coatings. Adding an aluminium foil intermediate in the double configuration improves the results of all wallpapers tested regarding radon reduction concentration, radon resistance, diffusion length and diffusion coefficient. Moreover, for the dense non-porous base made of non-woven fabric with a vinyl coating layer wallpaper, the diffusion length is shorter than the thickness of the sample in this configuration so the amount of penetrating radon will be reduced by the decay of radon in the wallpaper. Therefore, most radon would disintegrate along the sample and the concentration in the interior space would be lower. These results open a new alternative to protect indoor spaces from radon that access through walls or building materials based on a simple, easy and low-cost technique.

Design stability charts for construction procedure of basement walls using staged bermed excavation: a parametric study

The construction of basement walls using discontinuous staged berms is based on excavating the central zone of a lot and leaving a lateral berm – which is then removed in phases with unexcavated sections (buttresses) remaining until a concrete wall is completed in the excavated areas. It is a commonly used technique in many nations, but its use is unsupported by regulations or scientific studies. This paper addresses the need for a analysis of this technique and makes a study of the geotechnical parameters of the subsoils where it is applied, as well as the commonly used practices. The research involved over 4000 finite element method calculations integrating geotechnical parameters with construction geometry. The results have enabled the preparation of four stability design charts based on linear polynomial surface adjustment for two project scenarios: with and without surcharge load. This paper proposes the use of these stability design charts for staged bermed excavations in a broad spectrum of soil types and the incorporation of a designer-defined safety level to ensure temporary stability. Additional charts are provided to assess the safety factor of projects once the geometries and geotechnical parameters of the subsoil are known.

In-plane seismic performance of precast concrete hollow-core slab panels for basement walls

In building structures, exterior basement walls should resist the soil pressure type earthquake load transmitted by the ground. Thus, the structural performance of the exterior basement walls is affected by in-plane seismic performance as well as out-of-plane load resistance. In the present study, for better constructability and cost-effectiveness of the exterior basement walls, conventional reinforced concrete walls were replaced with precast hollow core slab (HCS) panels. To investigate the in-plane earthquake load resistance of HCS for exterior basement walls, cyclic lateral loading test and numerical analysis were performed on four HCS panels with in-plane double curvature. The test and analysis results showed that the structural behavior of the HCS panels was significantly affected by the panel layout. In the test specimens using a single panel, flexural compression failure occurred at the bottom of the panel, and shear friction damage occurred at the upper and lower parts of the panel. In the test specimens using double panels, failure mode was governed by direct shear. The load-carrying capacity of the test specimens using double panels was greater than two times that of the test specimens using a single panel, because the load transfer changed from flexure into direct shear in the wall specimens using double panels. Further, to use HCS panels for exterior basement walls, a design method for prediction of in-plane seismic performance and yield displacement of HCS panels was proposed.

Moisture and mould growth risk of cross-laminated timber basement walls: Laboratory and field investigation

Reinforced concrete is a commonly used material for constructing basements in low-rise buildings or residential houses in Canada, and as the use of cross-laminated timber (CLT) advances, the door to think of an alternative basement material to offset greenhouse gas emissions associated with reinforced concrete is open. However, the evaluation of CLT durability in below-grade environments, specifically concerning moisture and mould development, remains an unexplored field in research. Hence, this paper aims to analyze CLT's moisture response and mould growth risk in below-grade environments using field and laboratory experiments. A laboratory experiment was carried out to test a waterproofing membrane solution selected to compose the wall assembly in the field experiment. A large-scale experimental CLT basement was built at a cohesive soil site in Edmonton, Canada. The field experiment involved monitoring the relative humidity, temperature, and soil volumetric water content of the CLT panels, which measure 3 m by 6 m in plan and 2 m deep. Data was collected for an extended period from June 2022 to July 2023. The VVT model, developed by Hukka and Viitanen (1999) and updated by Viitanen et al., 2011 to estimate the mould growth level, was used to predict the risk of mould growth. The laboratory experiment showed that the waterproofing membrane is suitable for protection against moisture in a still-water setup. Field experiment results suggested that the primary moisture source was below the basement floor when the floor was finished inadequately. The moisture content of CLT walls was significantly increased by floor flooding and decreased by heating the basement interior. The acceptable mould index of three was surpassed during periods of abundant water below the basement floor due to flood events, showing that the CLT panels were at risk of mould growth development.

Dynamic Soil Pressure Acting on Building Basement According to Embedment Depth

ABSTRACT In the present study, centrifuge tests for small-scale specimens were performed to investigate the dynamic soil pressure of the basement of buildings subjected to seismic ground motions. To investigate the effect of the embedded depth of basement, a deep basement model fixed to rock (model 1) and a shallow basement model embedded in soil (model 2) were tested. The soil pressures acting at the front wall (Dynamic soil pressure, DSP) and back wall (Soil pressure at back wall, BSP) were measured. Under the Northridge earthquake (with PGAb = 0.33 g), DSP of Model 1 (fixed based model) reached 100 kPa showing an increasing linear distribution from bottom to top. The DSP profile was similar to the profile of relative displacement between the basement and soil. Interestingly, BSP decreased to 0 as a gap occurred between the soil and basement wall. On the other hand, in the case of model 2 with a smaller depth, the relative displacement between the basement and soil was smaller due to the influence of flexible base. As a result, DSP (<20 kPa) was smaller and BSP was greater than those of the deep basement model fixed to rock. The tested soil pressures were compared with the predictions of existing models.

Assessment of the effect of moisture on the strength of concrete and ceramic masonry wall products

Introduction. The material of the article considers the strength characteristics of ceramic and concrete masonry products, the operation of which is carried out in difficult conditions. The analysis of domestic and foreign publications and sources carried out in this work, including the results of previously performed experiments and field studies, showed that the values of the tensile strength of concrete and ceramic masonry products largely depend on moisture saturation.&#x0D; &#x0D; Aim. When analyzing previously performed works, it was found that moisture saturation and operating conditions significantly affect the strength properties of concrete and ceramic masonry products in the form of bricks and small blocks. It is noted that in some cases, the effect of degradation of the physical and mechanical properties of the products was observed. When performing surveys of buildings and structures, it becomes necessary to determine the bearing capacity of the masonry of foundations and basement walls located below the mark of the adjacent ground surface. These structures are located in an environment of excessive humidity, therefore, the masonry products themselves are in a state of increased moisture saturation, for example, due to the absence or damage of waterproofing, violation of the heat and humidity regime of the indoor microclimate.&#x0D; &#x0D; Materials and methods. During the work, masonry ceramic products in the form of bricks were used – new ones made according to State Standard 530-2012; historical bricks selected during the inspection of buildings and structures of historical buildings, as well as concrete wall products made according to State Standard 6133-2019. The test procedure complies with the established standard State Standard R 58527-2019.&#x0D; &#x0D; Results. Conducting of the research and developing of methods to assess the effect of humidification of ceramic and concrete masonry products on the strength of masonry is important for assessing the reliability of buildings and structures.&#x0D; &#x0D; Conclusions. The current problem requires comprehensive studies of the strength characteristics of ceramic and concrete masonry wall products, taking into account the influence of humidity.

The Role of Utilizing Load in Different Cases While Numerical Modeling of Multi-story Buildings on Alluvial Stratum: A Comparison Study

Industrialization and population growth have made surface areas more valuable, thereby the multi-story buildings have become an absolute necessity. At this point, numeric models became the fastest and simplest way to evaluate the response of soils and structures. The issued factor in the current paper is related to the way of transferring the multi-story building loads to an alluvial stratum and evaluate the accuracy of different cases, in order to save time and economy. For load transfer, the first case (case i) includes uniform distributed load, the second case (case ii) includes the transfer from the basement columns and walls, and the third case (case iii) includes modeling the real state of the building. Mainly, all three cases gave close results in terms of settlement magnitudes of 2.21, 1.96, and 1.81 cm, respectively. It was inspected that case (i) showed 12.8% more deformation than case (ii) and 22.1% more deformation than case (iii). However, the situation is not the same for the settlement pattern, and the under-column and corner effects are neglected in uniform load. Additionally, the bending moments, which is a critical parameter for the design of a reinforced concrete foundation, have developed different results. In case (ii) and (iii) a bending moment of 500 kNm/m is observed in the center column, while in case (i) the moments converge to 0. Therefore, this study highlights the importance of outstanding decision making when assessing the load-transferring mechanism in modeling with numerical methods. The necessity of the determination of the convenient load transfer way depending on the parameter that is crucial in the evaluation of the soil–structure interaction comes to the fore with current paper.

Performance of concrete superficially treated with nano-modified coatings under sulfuric acid exposures

Protection of concrete surface layer is crucial for preserving serviceability and durability of concrete structures during their service life. Chemical attack by sulfuric acid is an aggressive exposure, commonly causing significant damage to concrete elements such as buildings' foundations and basement walls, buildings and structures affected by acid rain, industrial facilities, and wastewater treatment facilities. Hence, this study endeavored to evaluate the performance of nano-modified composites as surface treatments for concrete under severe chemical exposures. Nano-calcium carbonate and nano-clay particles were dispersed at different dosages (0, 2.5, and 5% by mass) in the neat coatings: vinyl ester (membrane-forming polymer) and silane (hydrophobic agent). Moreover, an amorphous colloidal silica (SiO2>50%) was also used as a superficial treatment for concrete. These coatings were applied to concrete specimens with water-to-binder ratios (w/b) of 0.40 (representing good quality/low penetrability concrete treated for prohibition of deterioration) and 0.60 (representing deteriorated/high penetrability concrete in need for rehabilitation). the wettability and initial transport characteristics of the coated concrete specimens were determined. In addition, the durability of superficially treated concrete specimens was examined under two aggressive exposures: full submergence in a 5% (by volume) sulfuric acid solution, and 5% sulfuric acid solution combined with wetting-drying cycles. During both exposures, the deterioration of concrete specimens was observed by visual inspection and quantified in terms of mass change. Furthermore, the damage mechanisms and coatings’ performance were studied by microstructural, mineralogical, and thermal analyses. The overall results showed that vinyl ester and vinyl ester nanocomposites significantly improved the durability of concrete specimens by an average of around 64% relative to that of the silane and silane nanocomposites; hence, they are recommended for field applications.

Static Response of Non-yielding Basement Walls with Different Material Properties

Static Response of Non-yielding Basement Walls with Different Material Properties

Evaluating The Basement Design of Low-Rise Building with Two-Stage Analysis using BIM Integration: Hangar Study Case

Building Information Modelling (BIM) has revolutionized the way the construction industry designs, constructs, and manages buildings. Certainly, the utilization of BIM can optimize the usage of materials in a construction project, considering the high level of concrete consumption globally and its significant environmental impact. The implementation of BIM is intended to calculate the volume of concrete and steel material usage in the design process of low-rise buildings with basements, exemplified in this case by a 5-story laboratory hangar with a 1-story basement. The building design is carried out through a two-stage analysis, which involves separating the upper portion from the lower portion of the structure. This analysis procedure is commonly conducted in building design with basements. When designing the lower portion, some practitioners often neglect the lateral soil forces in the global model when designing the column and beam elements, assuming that these forces are sufficiently small and can be accommodated by basement wall reinforcement. In this research, with a shallow basement depth configuration, the study compares the extent of differences in structural dimensions and materials caused by these lateral forces. Significant variations in volume are observed in perimeter columns, primarily due to direct soil loads acting on this area. Additionally, considering the function of these columns as boundary elements for the basement walls, such differences are expected. The application of lateral soil forces on basement walls is determined by the specific basement configuration being designed. This includes assessing whether there are additional walls outside the basement walls, which can be analyzed locally since they are assumed to bear the lateral soil loads occurring. Different analyses yield varying reinforcement and concrete volumes in basement structures, especially between models with and without lateral soil loads, resulting in a 7.73% difference in reinforcement and 4.69% difference in concrete volume.

At-rest lateral earth pressure coefficient under narrow backfill widths: A numerical investigation

&lt;abstract&gt; &lt;p&gt;The lateral earth pressure at rest is typically considered in situations where lateral wall movements are negligible. Determining the coefficient of lateral earth pressure at rest (referred to as &lt;italic&gt;K&lt;/italic&gt;&lt;sub&gt;0&lt;/sub&gt;) often relies on established classical equations. However, these equations often overlook the influence of the width of the backfill soil on lateral earth pressure. While this omission is generally acceptable when the backfill soil is wide enough, there are instances where a retaining wall supports backfill soils of limited width, such as basement walls between adjacent buildings. Yet, there is limited research addressing the impact of narrow backfill in such scenarios. We aimed to address this gap by investigating variations in &lt;italic&gt;K&lt;/italic&gt;&lt;sub&gt;0&lt;/sub&gt; values under different conditions, including backfill width and soil properties. Using ABAQUS for numerical simulations, we refined and validated our model using relevant laboratory experimental data. Subsequently, the validated model was applied to various simulation scenarios. For narrow backfill widths (ranging from 0.1 to 0.7 times the retaining wall height), our findings indicated a general decrease in &lt;italic&gt;K&lt;/italic&gt;&lt;sub&gt;0&lt;/sub&gt; values with decreasing backfill widths, often smaller than those estimated using classical equations. Additionally, along the depth of the wall, &lt;italic&gt;K&lt;/italic&gt;&lt;sub&gt;0&lt;/sub&gt; values tended to decrease with increasing depth for narrow backfill widths. These findings contribute to our understanding of the impact of narrow backfill on &lt;italic&gt;K&lt;/italic&gt;&lt;sub&gt;0&lt;/sub&gt;.&lt;/p&gt; &lt;/abstract&gt;

Effect of soil-building interaction on dynamic earth pressure of basement walls using numerical analysis

Effect of soil-building interaction on dynamic earth pressure of basement walls using numerical analysis

Analysis of Seismic Earth Pressure Acting on Basement Walls of Buildings Using 1g Shaking Table Model Test

Analysis of Seismic Earth Pressure Acting on Basement Walls of Buildings Using 1g Shaking Table Model Test

A Comparison of Reinforcement Planning for Basement Wall Shelter Based on SS EN 1990: 2008 (2015) with Technical Requirements for Household Shelter 2023

Singapore is an example that applies the concept of household housing, namely buildings that are used as evacuation places. One of the buildings that applies the household residential concept is a detached type of residential house with a basement located at 102 Jalan Langgar Bedok, Bedok Planning Area, Singapore in an HDB housing block. The technical guidebook used as a guideline for building household shelters is "2023 Household Shelter Technical Requirements". The aim of this research is to compare household reinforcement shelter planning based on SS EN 1990: 2008 (2015) with the 2023 Household Shelter Technical Requirements. The method used in this research is a quantitative method using secondary data, namely the dimensions of the household shelter building and the results on-site survey. The results of this research show that when planning reinforcement using SS EN 1990: 2008 (2015), the diameter of the reinforcement used is larger, namely H16-100, compared to the 2023 Household Shelter Technical Requirements guidebook, namely H10-100. This is because the walls of household shelters are also used as basement walls.

Design solutions construction measures of basement wall using secant-pile technology

Nowadays, projects have one or more basements to serve the skyrocketing demand for parking, creating a need to develop many basement wall construction technologies to suit different geological conditions depending on the project location and location. construction function. In addition, the need to speed up construction progress and ensure construction quality requires continuously developing construction technologies. The article presents some experiences in designing construction methods to ensure the safety of construction structures, optimize costs and ensure construction progress.

Study on the anti-floating water level of the underground structure's comprehensive anti-floating

A significant amount of groundwater is in the underground rock and soil, which can exert buoyancy force on the underground structure. In severe cases, this can result in damage, such as cracking of basement walls and arching of floors. Single-using passive anti-floating measures cannot actively reduce the water load of the underground structure when a sudden high water level occurs. Single-using active anti-floating measures may cause environmental problems, and the reliability and durability of the system are difficult to guarantee. This paper adopted the comprehensive anti-floating method of active and passive combination, and the water level distribution function was established based on the measured data of the groundwater depth. The relationship between the normal water level (NWL) and the failure probability of passive anti-floating, which is the starting probability of active anti-floating (SPAA), was obtained. Then, according to the soil properties of the substrate where the active anti-floating system was located, the design service life of the building, the building function, and how the active anti-floating system affected the surrounding environment, assess the harm caused by exceeding the NWL, select the appropriate SPAA, and determine the NWL, which is the anti-floating water level (AWL) of passive anti-floating. Conventional passive anti-floating measures control groundwater below the NWL. When the water level exceeds the NWL, active anti-floating measures of active pressure relief are adopted. Whether groundwater rises or falls, it will not cause structural anti-floating failure. Reasonably selecting the anti-floating program and AWL ensure the underground structure's anti-floating effect to achieve a balance between its safety and economic viability. The new method was theoretically analyzed using measured one-year groundwater depth data from an observation well in Beijing's Fangshan District.

Flexural Behavior of Slabs with Different Anchorage Locations of Longitudinal Reinforcing Bars in a Composite Basement Wall Junction

Although the anchorage location of longitudinal reinforcing bars is a significant design element for flexural behavior, the conventional anchorage method of using longitudinal reinforcing bars has limited applications in new types of structures, such as composite structures. Therefore, this study examined the effect of the anchorage location of longitudinal reinforcing bars on the flexural behavior of slabs at the junctions of developed composite basement walls (SCBW) under monotonic loads at the top free end of the slab. The test results showed that the slab with longitudinal reinforcing bars anchored to the cast-in-place pile (CIP) in the composite basement wall exhibited ductile behavior accompanied by the yielding of the longitudinal reinforcing bars, a relatively wide area of vertical cracks propagating along the slab length, and a plastic plateau flow in the load–deflection relationships. In particular, the slab with longitudinal reinforcing bars anchored to the basement wall experienced severe crack concentration localized at the junction of the composite basement walls and concrete spalling in the basement walls, which resulted in no yielding of the longitudinal reinforcing bars and no cracks in the slab. Consequently, in a slab, it is recommended that longitudinal reinforcing bars be anchored into the CIP by penetrating the steel plate.

Flexural tests on composite basement walls with socket-type shear connectors

The effect of a recently developed socket-type shear connector (SSC) on the flexural behaviour of a composite basement wall (CBW) was examined in this work. To this end, 12 CBWs composed of cast-in-place (CIP) piles fabricated with H-shaped steel beams or reinforcing steel plates were prepared by varying the arrangement and amount of SSCs. Two-point loading was applied to simply supported CBW specimens. The CBW specimens with more SSCs had a higher effective stiffness in the elastic state and higher moment capacity in the ultimate state, irrespective of the cross-sectional details of the CIP piles. These trends were particularly prominent when a reinforcing steel plate was used in the SSCs. The post-peak behaviour of the CBW specimens subjected to a simulated load with a negative external moment tended to be more ductile. Consequently, a higher degree of composite action was fully exerted on the CBWs with greater numbers of SSCs. Using established equations for the sectional details of CBWs with SSCs, the nominal partially composite to full composite flexural capacity ratios of the CBW specimens subjected to simulated loads with positive and negative external moments were calculated to be, respectively, 0.83 and 0.91 for 0.5ηsc and 0.79 and 0.90 for 0.75ηsc, where ηsc is the normalised shear connector capacity specified in ANSI/AISC 360-16.