Underground Floor Research Articles

Stress-strain state of building structures taking into account possible local failure of the element

The issue of choosing a structural design and material for supporting structures is an important technical and economic task at the stage of developing a design solution. It depends on a number of factors: consequence class of the structure, reliability of the design solution, savings in basic building materials. The publication provides a classification of design schemes and types of load-bearing structures used in the corresponding solutions. The disadvantages and advantages of using prefabricated and monolithic structures for the installation and subsequent operation of the structural scheme of buildings and structures are considered. Modern design requirements include ensuring the ability of a damaged structure to adapt to new conditions while continuing to function while ensuring the integrity of human life, property and equipment. New conditions mean the consequences of the occurrence of a certain emergency situation, accompanied by weakening or overloading of the load-bearing structures of a structure or soil foundation: a change in the structural design, a combination of new existing loads and a redistribution of internal forces. The publication reflects the results of assessing the redistribution of the stress-strain state of the elements of the “base - foundations - load-bearing structures” system as a result of the implementation of a hypothetical emergency situation with the exclusion of the load-bearing structure from operation. The case of the collapse of one of the vertical load-bearing elements (local failure of the pylon) of an underground floor, which can be used as a dual-use structure, is considered. Calculations for the stability of the structure against progressive collapse were carried out by numerical modeling in the LIRA SAPR-2019 software using a quasi-static calculation and the method of direct integration of dynamics over time. It has been demonstrated that the method of numerical modeling the joint work of a building with a soil base affects the results of a calculation of the progressive collapse of the building frame. The influence of local collapse of a vertical load-bearing element on the redistribution of stresses and strains in the foundation structures of a building section is assessed. The load on the piles under the pylons around the element removed under the local failure scenario is expected to increase by 15...25%.

CRITERIA ANALYSIS FOR SELECTION OF A FIRE PROTECTION SYSTEM FOR AN OFFICE BUILDING

This article describes selecting a fire protection system that would be the most appropriate foran office building. This selection has been executed with the use of the APEKS multi-criteriamethod. The scope of work comprises the design of a hydrant system, which includes a designof a sprinkler system for three above-ground floors and one underground floor, supplied withwater from the municipal mains. Hydraulic calculations are also presented, with a cost estimatebased on catalogues obtained from the various companies. The entire project has been designed inpursuance of regulations and standards applicable in Poland with regard to the relevant buildingand fire protection regulations.

Reduction of additional pressure from ground construction on the subway escalator tunnel

The study considered options for reducing the additional pressure from the construction of a single-storey building on the underground structures of a deep shallow metro station. In the 3D formulation, the efficiency of the unloading «bridge» over the escalator tunnel was evaluated by the finite element method. It was found that the stiffer the grillage plate of the unloading «bridge», the more effectively the additional pressure from the building is transferred to the soils below the bottom of the escalator tunnel. However, in this case it is impossible to completely eliminate the additional pressure. In this regard, the option of creating an underground floor was considered. In this case, the weight of the selected from the excavation soil compensates the load from the building. The required depth of the basement floor was determined analytically, calculations were performed in characteristic sections on 2D models, and the operation of all structures in combination was considered on a general 3D model. Based on the results of the study, a rational algorithm was proposed for calculating the additional pressure from ground construction on underground subway structures.

A Dynamic Model for Effective and Optimal Planning of Formwork in Construction Projects

The cost of producing one cubic meter of concrete structure, depending on the structure’s shape, type, and complexity, can be variously high. The cost of concrete, reinforcement, formwork, and labor ratio varies. But unlike the cost of concrete and reinforcement, which tend to be similar in the terms of the conditions of a particular construction project, the cost of formwork and work with it are different for different contractors. It often depends on the appropriateness of the formwork system used, the optimal placement of the formwork sets, the minimization of downtime, and the efficiency of the carpenters’ work. Formwork modeling in the construction preparation phase intervenes in this planning area, where construction sources are defined and quantified, and the time course of their deployment is determined. The current paper deals with optimizing formwork selection and deployment in concrete structure execution. Even if several requirements must be considered when selecting and modeling the formwork (e.g., construction time, quality of concrete structure, etc.), an effort to minimize the cost of formwork, and thus construction cost, plays the most significant role. A dynamic model for effective and optimal planning of formwork in construction projects, including formwork cost analysis, is presented in the paper. The included case study demonstrated the planning of the formwork through a software application developed based on the computational algorithm of the dynamic model presented. A case study is presented in the article as a research method. An office building with five above-ground floors and one underground floor was chosen for the case study. To solve the case study, the formwork for horizontal structures (i.e., beams and slabs) is considered. The goal of the case study is to identify research questions and apply time and cost optimization to a selected specific building.

DOCUMENTATION OF COMPLEX ENVIRONMENTS IN CULTURAL HERITAGE SITES. A SLAM-BASED SURVEY IN THE CASTELLO DEL VALENTINO BASEMENT

Abstract. Underground Built Heritage (UBH) stands out among the existing Cultural Heritage sites as a peculiar scenario. The assets belonging to this type of heritage are typically difficult to manage, exploit, and promote because of a lack of knowledge and documentation. The challenges in documenting built heritage are many and wide-ranging, and the main need must be to provide an accurate and appropriate representation of the surveyed area and its geometric features without employing time-consuming processes. Mobile Mapping Systems (MMSs) are nowadays trending technologies for the geomatics community, proving to be a useful alternative to traditional surveying techniques when taking time and cost constraints into account.The paper focuses on the use of an MMS, the STONEX® X120GO SLAM Laser Scanner system, in documenting a portion of the Castello del Valentino, an articulated and complex architecture located in Turin (Italy). The underground floor of the castle, due to its complexity in terms of accessibility and the challenge it poses for the documentation approach, was chosen as a case study to assess the STONEX® X120GO's capabilities in terms of portability of the instrument, speed of acquisition, as well as completeness and accuracy of the acquired dataset. The results obtained using the MMS technique have been compared to and validated using data from a TLS (Terrestrial Laser Scanner) survey used as a ground reference. The results and considerations reported in this paper demonstrate that MMSs can accurately and completely depict built spaces and their main characteristics and have substantial potential in mapping complex assets.

Oxidative stress and chemical characteristics of indoor PM2.5: a case study in an underground (-3rd) floor

Oxidative stress and chemical characteristics of indoor PM2.5: a case study in an underground (-3rd) floor

Optimal multiobjective design of guidance information systems in underground spaces: Model development and a transportation hub case study

Guidance information systems (GISs) are widely used for pedestrian navigation in underground spaces. We investigate GIS design methods in this paper. First, the information demand and potential information locations are abstracted based on the network discretization of underground spaces. Second, a multiobjective GIS design (MOGISD) model that focuses on economic costs and wayfinding is developed, and a dynamic solution evaluation-based heuristic algorithm is proposed to determine the optimal GIS design plan. To obtain a GIS plan that can achieve a perfect match between demand and information, a three-dimensional microscopic pedestrian-information interaction model that considers both human and information factors is formulated. Finally, to evaluate the effectiveness of the MOGISD model, we use the model to design a GIS plan for the underground floor of a multimodal transportation hub. The results show that the proposed method produces cost-effective GIS design plans contributing to high-efficiency wayfinding. The MOGISD model is designer-friendly due to the simultaneous optimization of signage location and information allocation plans.

Lowering water level in an excavation for a multi-family residential building in urban development

The paper concerns lowering water level in excavations for residential buildings in a dense urban development. The construction and protection of excavation walls as well as the methods of lowering the water level and its impact on the surroundings were discussed. An excavation dewatering system is presented on the example of a multi-family residential building with one underground floor, built in dense urban development. The excavation executed in the sandy subsoil below the groundwater level and encased with walls made of steel sheet piles was analysed. Two concepts of lowering the water level in the excavation were considered: the first with use of a wellpoint system, the second with use of a well with pumps. The conducted calculations showed that when using a wellpoint system to lower the water level in the excavation for analysed multi-family residential building, a system consisting of 260 wellpoints with a spacing of 1.0 m should be made. The efficiency of a single wellpoint is 12.25 m3·d–1, and the efficiency of the entire installation is 3,185.69 m3·d–1. When draining the wells, a system consisting of 9 wells should be made, with a unit capacity of 375.58 m3·d–1 and efficiency of the total installation 3,380.22 m3·d–1.

Linearity

In January 2021, Saudi Crown Prince Mohammed bin Salman Al Saud launched The Line city project. Even for the Saudis’ fantastical ambitions, the project looks amazing: a city stretched along a straight line for 170 kilometers across the sandy desert from the Red Sea coast to the capital of the mountainous Tabuk province. The city will have three floors: a pedestrian zone on the surface, service infrastructure on the underground floor, and on the floor below there will be highspeed railways. It seems ironic that the ideas of a linear city, which were actively developed in the USSR, find large-scale implementation in a country with an absolute monarchy. Why do the ideas of a linear city come to life in our present-day world? How are these ideas transformed by digital technologies? How is the very notion of linearity changing as the fabric of the city becomes increasingly virtual and roads are replaced by 5G channels? As usual, we do not claim to have a comprehensive set of answers to these questions related to the cutting edge of urban theory and philosophy of the city. But is it just the city? Giant projects of the revival of the Great Silk Road, the concept of the Eastern pivot and Greater Eurasia form the image of a linear continent – not a city, but a giant complex of many cities in a number of countries. A group of architects from sub-Saharan Africa is initiating the Great Green Wall competition: a great band of green oases is to block the hot breath of the desert and mitigate the climate of the entire equatorial Africa. Today linearity looks like a global challenge and at the same time a strict condition for development on the most diverse levels: neighbourhood, city, region, continent, and humanity.

Cost Modeling from the Contractor Perspective: Application to Residential and Office Buildings

For the majority of the contractual arrangements used in construction projects, the owner is not responsible for the cost deviations due to the variability of labor productivity or material price, amongst many other aspects. Consequently, the cost performance of a project may be entirely distinct for the owner and the contractor. Since the majority of quantitative research on cost estimation and deviation found in the literature adopts the owners’ perspective, this research provides a contribution towards modeling costs and cost deviation from a contractor’s perspective. From an initial sample of 13 residential buildings and 10 office building projects, it was possible to develop models for cost estimation at the early stage of development, including both endogenous and exogenous variables. Although the sample is relatively small, the authors were able to fully analyze all the cost data, using no secondary sources of data (which is very frequent in cost modeling studies). The statistically significant variables in the cost estimation models were the areas above and below ground and the years following the 2008 financial crisis, including the international bailout (2011–2014) period. For estimating the unit cost, a nonlinear model was obtained with the number of underground and total floor, the floor ratio, and the years following the 2008 financial crisis, including the international bailout (2011–2014) period as predictors. For the office buildings, a statistically significant correlation was also found between the cost deviation and number of underground floors.

Evacuation Optimization of a Typical Multi-exit Subway Station: Overall partition and local railing

In the process in which high-density passengers need to be evacuated from a multi-exit subway station, not all the exits can be effectively utilized, and the bottlenecks near the exits are often crowded. Therefore, the utilization of different exits and the optimization of congestion at bottlenecks were investigated in this study. To alleviate the congestion of the evacuation in a large-scale and multifunctional subway station, the first underground floor of the station was divided into four regions, referring to the idea of fire compartment division, in which passengers were evacuated from local exits. The results reveal that the evacuation time increases as the initial passenger density increases. The railings have a positive effect on balancing the proportion of different exits for the region with fewer exits in the early evacuation stage. For regions with several exits well-distributed, the symmetrical structure is beneficial to the evacuation and the effective use of different exits. What's more, setting railings can reduce crowding at bottlenecks to a certain extent. The results of the study can guide passenger evacuation in typical multi-exit subway stations.

Performance of Mortars Made Using Ternary Binders with Addition of Slag, Fly Ash and Limestone Exposed to a Real Environmental Condition Compatible with Exposure Class XC3.

The use of eco-friendly cements prepared with ternary binders could contribute to improving the sustainability of cement production. However, their use for manufacturing commercial cements is very low, at least in Spain. The purpose of this research is to study the behavior in the long term of mortars made with ternary binders which incorporated ground granulated blast furnace slag, fly ash, and limestone, exposed to environmental conditions compatible with the specifications of exposure class XC3 of the Eurocode 2, compared to mortars without additions and mortars with binary binders. The exposure station was placed in an underground floor of a building used as a garage with circulation of vehicles and moderately high CO2 concentration. The ternary and binary binders verified the prescriptions of cement type CEM II/B. The microstructure was characterized using mercury intrusion porosimetry and electrical resistivity. Water absorption, diffusion coefficient, carbonation depth, mechanical strengths, and ultrasonic pulse velocity were determined. A loss of microstructure refinement with time was noted for all the analyzed binders, probably related to the development of carbonation and drying shrinkage. The binary mortars with slag and fly ash and the ternary binder which combined them showed the best mechanical performance at 250 days.

Prevention of Water Inrushes in Deep Coal Mining over the Ordovician Aquifer: A Case Study in the Wutongzhuang Coal Mine of China

Through field observation and theoretical study, we found that the Hanxing mining area has a typical ternary structure in coal mining under high water pressure of the aquifer. This ternary structure is the Ordovician limestone aquifer-aquiclude including thin limestones-coal seam. Although the aquiclude is considerably thick, there is still a great risk of water burst during mining under water pressure in the deep burial environment. Multidimensional characteristics of floor water inrush in deep mining are summarized in the paper, including water migration upwardly driven by the Ordovician confined water, the planar dispersion of the water inrush channel, the stepped increase of the water inrush intensity, the hysteretic effluent of the water inrush time and the exchange, and adsorption of the water quality. The water inrush mechanism is clarified that the permeability, dilatancy, fracturing, and ascending of the water from the Ordovician limestone aquifer form a planar and divergent flow through the transfer, storage, and transportation of thin limestone aquifers. The corresponding water inrush risk evaluation equation is also proposed. Based on the thickness of the aquiclude, the thickness of the failure zones, and the water inrush coefficient, the floor aquiclude is classified into five categories. While water inrush cannot be completely controlled by the traditional underground floor reinforcement with ultra-thick aquiclude or even zonal grouting, a comprehensive prevention and control concept of the four-dimensional floor water hazard in full time-space domain are proposed. A tridimensional prevention and control model of three-dimensional reticulated exploration, treatment, verification, and supplementation is presented. A full time domain technological quality control process of condition assessment, exploration, remediation, inspection, evaluation, monitoring, and reassurance is formed, and a water disaster prevention method with full time-space tridimensional network in deep coal mining is established. Case study in the Hanxing mining area demonstrates that the proposed methods are highly effective.

The Use of 3D Numerical Modeling in Conceptual Design: A Case Study

This article describes the construction of a building with four aboveground floors and one underground floor as part of the ongoing development of Warsaw’s city center. A 3D numerical model was developed to reflect the spatial and structural solutions of the new building based on the design documentation with regard to the outcomes of geotechnical tests, the actual phases of work completed, the results of the geodetic measurements carried out in individual phases of the building implementation, and the characteristics of the existing adjacent buildings. The 3D numerical model was calibrated taking into account the results of the geodetic measurements of the benchmarks stabilized on the adjacent buildings. The numerical models of the building were used to analyze a number of multiple-step variants, taking into account the increase in the number of aboveground floors (from 1 to 4) and underground floors (by 1), as well as the increase in the projected area of the underground part compared to the area of the site designated for development. The paper presents the conclusions of our analyses, which may be helpful to others designing buildings in intensively urbanized areas and guide them in selecting the best solution.

Nonsteady Heat Loses to the Ground from a Building with Heated Underground Floor or Slab on Ground

Numerical model and research results of nonsteady heat transfer between building and ground basement are in the article. Two most common cases of heat contact between building and ground basement are compared: building with heated underground floor and building on the slab on ground. Nonsteady heat loses over period about several years of building exploitation are analyzed that made possible to establish a patterns of heat transfer between building and ground with taking into account of ground around of building inertness. Heat loses from building represented using mean values at the one unit of length of building perimeter. In case of building with underground floor calculated nonsteady heat loses of floor and underground wall are shown. Also shown results of nonsteady heat transfer to ground from outdoor air and groundwater. Numerical methodic used in research based on explicit finite-difference method applicated to boundary value problem of nonsteady heat transfer in ground. The problem taking into account existence of moveable groundwater without heat transfer calculation in the volume of groundwater.

Numerical simulation of the seismic response and soil\u2013structure interaction for a monitored masonry school building damaged by the 2016 Central Italy earthquake

Despite significant research advances on the seismic response analysis, there is still an urgent need for validation of numerical simulation methods for prediction of earthquake response and damage. In this respect, seismic monitoring networks and proper modelling can further support validation studies, allowing more realistic simulations of what earthquakes can produce. This paper discusses the seismic response of the “Pietro Capuzi” school in Visso, a village located in the Marche region (Italy) that was severely damaged by the 2016–2017 Central Italy earthquake sequence. The school was a two-story masonry structure founded on simple enlargements of its load-bearing walls, partially embedded in the alluvial loose soils of the Nera river. The structure was monitored as a strategic building by the Italian Seismic Observatory of Structures (OSS), which provided acceleration records under both ambient noise and the three mainshocks of the seismic sequence. The evolution of the damage pattern following each one of the three mainshocks was provided by on-site survey integrated by OSS data. Data on the dynamic soil properties was available from the seismic microzonation study of the Visso village and proved useful in the development of a reliable geotechnical model of the subsoil. The equivalent frame (EF) approach was adopted to simulate the nonlinear response of the school building through both fixed-base and compliant-base models, to assess the likely influence of soil–structure interaction on the building performance. The ambient noise records allowed for an accurate calibration of the soil–structure model. The seismic response of the masonry building to the whole sequence of the three mainshocks was then simulated by nonlinear time history analyses by using the horizontal accelerations recorded at the underground floor as input motions. Numerical results are validated against the evidence on structural response in terms of both incremental damage and global shear force–displacement relationships. The comparisons are satisfactory, corroborating the reliability of the compliant-base approach as applied to the EF model and its computational efficiency to simulate the soil–foundation–structure interaction in the case of masonry buildings.

Structural design of residential buildings according to Eurocode

In this paper, the dimensioning of the load-bearing structures A, B and C of building complex in the surroundings of Salzburg, Austria is given. The floors of object A are underground floor, ground floor and two floors, and for objects B and C it is underground floor, ground floor, first floor and the attic. These buildings have an underground shared garage. The foundation is 30 cm thick reinforced concrete slab, with capitals 200/200 cm, thickness dpp = 20 cm that are constructed in the middle part of the garage under the columns. Other underground parts of the buildings are the basements of each individual building. In addition to the common garage, the buildings have a common part of the ground floor, which connects the separate buildings. The construction of the garage at ground level is in the form of reinforced concrete slab with thickness dp = 35 cm with reinforcement-capitals under the columns with thickness dkpl. = 20 cm. The foundation and the ground floor slab are separated by an expansion joint in the axis 7. The waterproofing of the ground floor slab is achieved uniquely for the whole slab of the complex. Special attention is paid to the thermal calculation.

Research on key technologies for construction of super-deep railways stations near existing lines in the flood land area of the Yangtze River

In this paper, taking Nanjing Mochou Lake Metro Station as an example, the key technologies for the construction of super-deep stations near existing lines in the flood land area of the Yangtze River are studied. Mochou Lake Station is located in Mochou Lake Park on the Qinhuai River. It is a four-level underground island-type platform station, which is interchanged with the existing Line 2 Mochou Lake Station. The station used the “two-light and two-dark” construction method. The first and the second underground floor of the station used an open excavation order method, and the third and the fourth underground floor used to cover and cut-bottom up method. According to the monitoring results and settlement analysis results of the main structure, the construction method of “two-, light and two-dark, ” can help control the deformation of the construction area and ensure the safety of the surrounding structures and existing stations.

Measurements with cosmic muons to monitor the stability of a civil building on a long time-scale

Due to their penetration capability, cosmic muons may provide a way to monitor the alignment and possible long term deformations of large structures, such as historical or other civil buildings. The basic idea behind this possibility is to look for any misalignment between position-sensitive detectors, fixed to different parts of the structure, relative to the original alignment condition. In this paper we discuss the possibility of employing Multigap Resistive Plate Chambers (MRPC) as tracking devices, operating them in coincidence with additional detectors without tracking capability. One of the MRPC telescopes (size 158× 82 cm2) of the Extreme Energy Events (EEE) project, installed in the underground floor at the Department of Physics and Astronomy in Catania, was used together with a 40× 60 cm2 scintillator-based detector, located at about 16 m vertical distance, on the third floor of the same building. Coincidence measurements were carried out over a period of about two months by shifting the position of the smaller detector, to mimic the movement of the structure. Plans for future studies with different detectors and under different geometrical configurations are also discussed.

A new coal mine floor rating system and its application to assess the potential of floor heave

Several underground coal mines have reported floor heave associated with the buckling mechanism. However, studies on the coal mine floor, especially the buckling failure mechanism in the floor and relevant analysis techniques, are still insufficient. This paper introduces a new floor classification system, the Coal Mine Floor Rating, based on the underlying failure mechanisms. The new floor mass rating system quantifies the stability of floor strata by considering two main factors: uniaxial compressive strength and discontinuity spacing of the floor units. The Coal Mine Floor Rating is incorporated into an empirical method, the Floor Heave Index, developed by statistical analysis of a database obtained from actual floor failure cases. The floor heave and non-floor heave cases are determined depending on the Coal Mine Floor Rating and the Horizontal Stress Rating, a proxy that represents the magnitude of horizontal stress. While obtaining underground floor data is challenging, the new floor classification system and the empirical method help assess the potential of significant floor heave on development in underground coal mine roadways for new mining projects or future workings.