Floor Construction Research Articles

Determination of the quality of coarse aggregates for the elaboration of concrete mixes from 3 water sources in the City of Cucuta-Colombia

A comparative analysis was performed on the mineral material extracted from 3 water sources in the city of Cucuta, from the rivers Tachira, Pamplonita and Zulia to determine the viability of their incorporation in the concrete mixtures for the construction of rigid floors. There were visits to the companies Preconcretos Trituradora la Roca y Concretos, and Tirurados, in charge of the material extractions, where samples of the crushed material “coarse aggregate” from each of the water sources were taken respectively. The granulometry of the coarse aggregate was performed according to the arranged parameters in the NCT 174 whose results were determinant for the conclusions. The trial of degradation to abrasion to each of the samples was executed, taking as guide the indications described by the Colombian INV-218-13 standard. The results obtained in the trial were analyzed and compared with the parameters stipulated by the INV standard described for the % of the degradation limit allowed for coarse aggregate for its usage as concrete material in the construction of rigid floors. It was concluded that each of the extracted materials from the water sources were viable according to the data obtained from their comparison.

Numerical analysis of ultra-high strength fibre-reinforced concrete slabs

Reactive Powder Concrete (RPC) is one the latest developments in concrete technology, also known as ultra-high-performance concrete (UHPC). It is characterised by the use of high cement content, with very high mechanical strength, high durability, in most cases, a quantity of steel fibres. A hollow core slab, also known as a void slab, hollow core plank, or simply a concrete slab is a precast concrete slab frequently used in the construction of floors in multi-story apartment buildings. The presence of holes in the reinforced concrete is necessary to act as ducts for services as well as having the structural purpose of reducing the weight of the slabs. This study examines previous experimental research results for 26 slabs in terms of examining the behaviours of reactive powder concrete slabs with longitudinal hollow cores of various sizes under various loading situations by changing the a/d ratio. The ANSYS computer program was used to investigate the behaviours of some of these slabs, and parametric studies were used to study the effects of the compressive strength of the concrete, types of support, and different steel reinforcement diameters. The results obtained using finite element solutions showed good agreement with experimental results.

Response of Asymmetric Slim Floor Beams in Parametric-Fires

State-of-the-art slim floor systems are a newest addition to the composite construction industry and several types are currently being used for building and construction purposes. Asymmetric slim floor beams are a type of slim floor systems which consist of a rolled section with a larger bottom flange. The larger bottom flange induces asymmetry and offers an efficient use of the material strength as a composite beam. It also offers a larger area to support the steel decking and pre-cast slab units during the construction of floor. Experimental and analytical investigations on response of asymmetric slim floor beams have shown that these beams offer a higher fire resistance in comparison to the conventional composite systems with down-stand steel beams. Previous investigations on these beams have been conducted in standard fire exposure conditions, hence, their response to natural fire scenarios still deems further examination. This study addresses response of asymmetric slim floor beams in natural fire exposure conditions. For this purpose, finite element models developed and verified by the authors are employed to study the thermal and structural response of slim floor beams in fast and slow parametric-fire exposures. Results obtained show that the asymmetric slim floor beams behave differently in parametric-fires in comparison to that in standard fire exposure conditions. Asymmetric slim floor beams continued to support the loads for the whole duration of parametric fires without undergoing excessive deflections and offering a better fire resistance. Unlike in case of the standard fire where the temperatures keep on increasing throughout the duration, temperatures on the slim floor beams decrease after reaching a maximum point in parametric-fires. It was found that for fast parametric-fires, the thermal gradient across the section is more severe as compared to that for the slow parametric-fires at earlier stages of fire exposure. In case of the fast parametric-fires, the rise and fall of temperatures on the slim floor beams are rapid while in case of the slow parametric-fire, these variations in temperatures are subtle. It was observed that the structural response of slim floor beams in standard and parametric fires depends on the average temperature across the steel section. Deflections predicted for the beams were found to be directly related to these average temperatures. Outcomes of this study will benefit in understanding the response of asymmetric slim floor beams in natural fire conditions and will aid to develop simple fire design methods for future use.

Using the ground as a heat sink in residential buildings during heat waves

Heat waves that are the result of climate changes have become an increasingly intense and therefore dangerous for human health and life. In the countries of moderate climate such as Poland, which have never before been experienced by such phenomena, residential buildings are usually free of overheating systems. In this paper authors propose a passive cooling method using the ground under thermally uninsulated floor slab as a heat sink for cooling the inside air during hot summer. The paper presents current knowledge of the authors gained as a result of theoretical analysis, fully confirmed by experimental research in two terraced rooms differing from each other only by the type of floor construction. Authors additionally presented the simulation results obtained for detached houses, which took also into account the effect of blinds in windows and increased night ventilation. The lack of ground floor thermal insulation significantly decreases the indoor air temperatures in the room with negligible “cold floor” effect. The duration of heat wave did not affect the effect of temperature reduction. Despite of the significantly difference in energy demands, it can be compensated by renewable energy sources.

Evaluation of floor vibration properties using measurements and calculations

Timber floor constructions are very common in the Nordic countries, for instance in single- and multifamily buildings. But building with wood is increasing in popularity for other building categories and there is wider interest in increasing the span width of wooden joist floors. Static and vibrational performance become crucial for serviceability of timber floors and often limit the design; however, constructors and designers want to increase the floor span width. To meet these challenges, reliable design methods are required and have therefore become a focus in many countries.This paper presents results from a number of measurements of different joist floor constructions. Parameters measured have also been calculated according to given equations and relevant methods. Both calculations and measurements include 17 laboratory objects and four field objects. The objects represent a huge variety of solutions and therefore a large spread of results. The main reason for the selection of floor solutions was to expand the possibilities and test the methods more than tuning current solutions into satisfactory floor vibration perception.The data and resulting analysis in this paper highlight benefits and limitations concerning relevant parameters for evaluation of floor vibration perception. According to this work, it is not possible to verify the Eurocode method with respect to accuracy, and the link to perception of floor vibrations is rather low. Another method should be used or developed for the future. Results presented in this paper show that sufficient accuracy may be achieved using parameters from the Hu and Chui (2004) method. Experiences from Norway over the last five years are also promising regarding evaluation of floor vibration perception using this method. However, attention should be given to floors with significantly lower damping properties and/or significantly higher (modal) masses. Damping properties or an alternative parameter taking a longer time interval of the vibrations into account should be considered.

From deposits to social practices: Integrated micromorphological analysis of floor sequences at Middle Bronze Age Erimi-Laonin tou Porakou, Cyprus

Floors are a key data-set of cultural evidence in archaeological contexts as they offer potential for detecting and interpreting the spatial conventions through which economic and social relationships are represented and negotiated during the life-history of buildings and settlements. In this study, floor sequences from the Middle Bronze Age site of Erimi-Laonin tou Porakou (c. 1950–1650 BCE) have been analysed through an interdisciplinary approach based on integration of stratigraphic, micromorphological, spectroscopic (FTIR) and geochemical (XRF) analyses. This integrated approach is aimed at examining materials and technology in floor plaster manufacture as well as the impact of environment and activities on floor surfaces as indicators of continuity and change in use of space and related socio-cultural and economic implications. The multi-scalar data-set provided an effective framework with which to reconstruct every-day practices in the construction, use and maintenance of floor plasters within buildings. In particular, data analysed has permitted identification of the occurrence of specific recipes in floor plaster manufacture that suggest organisation of labour and production possibly at supra-household level. However, no clear evidence of pyrotechnological plasters has been recognised on the basis of data examined. Spatial and temporal changes in floor sequences reveal that floor plastering episodes represented important markers of building renovation during the life history of Erimi-Laonin tou Porakou. Instances were documented of the introduction of layers of new floor plaster types that corresponded to changes in activities within building, from dirtier to cleaner, and to enhancement of spatial and architectural elaboration of built space. The integrated micromorphological analysis applied to floor plaster sequences has provided new insights into the dynamic scenario of social organisation at Erimi-Loanin tou Porakou, contributing to delineation of a range of potential avenues for studying socio-cultural trajectories and evolutionary pathways of Bronze Age communities in Cyprus.

Experimental investigation on ferritic stainless steel composite slabs

Steel-concrete composite structures are well established in the construction of floors and roofing, being interesting solutions as steel decks act as formwork for relatively large spans and support the weight of the concrete and construction loads. However, the use of stainless steel decks in such structures has been very limited, although their mechanical properties, corrosion resistance, aesthetics and emissivity make them excellent for visually exposed composite floor slabs where the thermal capacity of the slab is mobilized as part of an energy saving strategy. This paper presents a comprehensive investigation on composite slabs with trapezoidal ferritic stainless steel decks in order to assess the performance of such structural members. Composite slabs made from EN1.4003 ferritic stainless steel and common C25/30 concrete were tested in two series of span lengths in order to determine the different parameters defining their ultimate longitudinal shear response. Reference tests on slabs with galvanized steel were also conducted with identical geometries and configurations. The m and k parameters used in the m-k Method and the design longitudinal shear strength τu,Rd corresponding to the Partial Connection Method have been determined according to EN 1994-1-1:2004. Finally, the behaviour of these composite slabs was compared with the performance shown by the conducted reference slabs with galvanized steel deck in terms of Ultimate and Serviceability Limit States.

Investigating the Meraka Hardwood Failure in Bolted Connections Parallel to the Timber Grain

The present study was performed to investigate the ductile failure mode of timber bolted connections, specifically in Meraka hardwood. This was done to initiate an effort in developing a comprehensive guideline in designing the timber bolted connections for the purpose of strengthening the wall-diaphragm connections of the Malaysia unreinforced masonry buildings. A series of experimental tests was conducted on the steel-wood-steel (SWS) with a single row connection type. A total of eight different bolted connection configurations or groups with ten replicates for each group was tested. The Meraka hardwood was selected in this study as it was found to be one of the most hardwood species that are commonly used in the construction of floor and roof diaphragms in the existing Malaysia unreinforced masonry buildings. From the experimental results obtained, the effectiveness of the Malaysian timber code of MS544 and European Yield Model (EYM) in predicting the bolted connection strength was verified. It was determined that the MS544 is too conservative in estimating the bolted connection strength with an average ratio of 0.38 compared to the test results. Thus, the use of the EYM is recommended to complement the timber code as the average ratio of 0.81 was identified in comparison to the test data.

Comparison of prediction tools to determine their reliability on calculating operational heating consumption by monitoring no-fines concrete dwellings

Nowadays most retrofit decisions are based on reducing CO2 / heating consumption. The aim of this study was to determine the reliability of three tools (RdSAP, SAP and IES) often used to predict these reductions. Three no-fines concrete (NFC) dwellings (C1, C2, and C3) with similar floor area and construction but different occupants were monitored. Key information about the thermal performance of the fabric; the behaviour of the occupants and the energy consumption was collected before and after 110 mm of external wall insulation (EWI) was added. The target was a 30% reduction on energy consumption due to the EWI. However, only C3 decreased it by 30% as expected, C2 only by 14% due to a subtle rebound effect and C1 actually increased consumption by 75%, due to rebound effect.Steady state tools (RdSAP and SAP) were found to be inaccurate in predicting the operational energy consumption of dwellings, only dynamic performance analysis software (IES) was suitable to carry out this type of prediction accurately. However, this type of software requires highly accurate and detailed information regarding: the baseline performance of the fabric, external weather conditions and, most importantly, accurate pre- and post- heating operational habits of the occupants. Few retrofitting projects have the resources and time to gather this information. Unless those are available, the retrofit decisions should be based in a different criteria, rather than using inaccurate SAP or RdSAP energy consumption predictions.The coefficient of heat loss of the fabric of a dwelling is independent of the occupants. SAP was found quick to calculate reasonable predictions of the coefficient, by using accurate fabric data, and to show the impact of different factors on the heat loss of the fabric. Therefore, it could be claimed that the coefficient of heat loss of the fabric is a suitable alternative criteria to make pre-retrofit decisions.

An industrial facility layout design method considering energy saving based on surplus rectangle fill algorithm

The facility layout design within a plant is a key step in the process of chemical engineering design. A good layout can save capital cost, energy and natural resource. The aim of this work is to determine the relative location of facilities in a large-scale industrial plant considering multi-floor structure to make the total cost minimum. The objective function consists of piping investment cost, pump power cost, land cost, and floor construction cost. Surplus rectangle fill algorithm is applied in this work, and it is combined with a genetic algorithm to obtain the optimal solution. Constraints of pump area, joint arrangement of heat exchangers, and the cross-floor facilities are also taken into consideration. In the case study, a plant from a real refinery including 217 facilities is designed with different floor number. The comparison of the three different conditions proves the important role of floor number in the trade-off among investment cost, energy consumption, and land resource. The case illustrates that, the proposed method can generate a reasonable layout design for the industrial facilities and save capital and operating cost effectively. A sensitivity analysis is also done to explore the influence of basic data on the optimal construction structure.

Experimental Analysis of MOC Composite with a Waste-Expanded Polypropylene-Based Aggregate.

Polypropylene (PP) is one of the most widely produced types of plastic worldwide, but its recycling is limited. This work presents a study of the utilization of expanded polypropylene (EPP) waste in a magnesium oxychloride cement (MOC) composite usable in the building industry. MOC is formed by mixing magnesium oxide powder and a concentrated solution of magnesium chloride and is characterized by excellent bonding ability to large quantities of different types of aggregates. A developed air-cured MOC composite, where an EPP-based aggregate was used for the full replacement of natural aggregate, was investigated in terms of its basic physical, mechanical, thermal and water resistance properties. The results demonstrate that incorporation of EPP waste greatly improved the thermal insulation properties, while the mechanical resistance was reduced to an acceptable level. The developed MOC composite containing EPP waste can be considered as an alternative thermal insulation material applicable for the construction of floor or envelope construction systems.

Estimating the influence of occupant behavior on building heating and cooling energy in one simulation run

Energy performance contracting (EPC) aims at guaranteeing a specified level of energy savings in the built environment for a client. Among the building energy performance uncertainties that hinder EPC, occupant behavior (OB) plays a major role. For this reason, energy service companies (ESCOs) may be interested in including OB-related clauses in their contracts. The inclusion of such a clause calls for an efficient, easy-to-implement method to provide a first estimate of the potential effect of various aspects of OB on building cooling and heating energy demand. In contrast with common sensitivity analysis approaches based on a high number of scenarios, a novel simulation method requiring only a single simulation run for both heating and cooling seasons is presented here. The estimate is provided by evaluating the newly developed impact indices (II) based on the results obtained by means of the simulation run. A set of 16 building variants differing in floor height, climate, construction vintage and equipment and lighting power density was investigated to test the method. All II were calculated for the 16 building variants. In order to verify their significance, the results of a one-at-a-time sensitivity analysis mimicking simplified variations in occupant behavior (OB) were plotted against the II. The R2 values were above 0.9 when evaluating the effect of equipment use, lights use, and occupant presence, confirming the significance of the developed II. For blind use and temperature setpoint setting, the R2 values were ca. 0.85. Subsequently, the method was applied to an existing office building in Delft, The Netherlands, to evaluate its potential for EPC. This study confirms the high variability of the effect of OB on heating and cooling energy demand according to the case at hand. The developed method is useful for practitioners to evaluate the potential effect of OB on a given design in a time-effective manner.

Effects of sub-base surface roughness on shrinkage cracking of industrial floors

Avoiding the formation of shrinkage cracks is one of the most important tasks in construction of concrete industrial floors. Cracks appear on the surface of floors when the nonlinear processes in the structure lead to internal stresses that exceed the actual tensile strength of the concrete. The tensile stresses developed depend on the constrained deformation of the floor during shrinkage and the elastic modulus of the material of the concrete slab. However, on the top surface of the floor, the tensile stresses can be increased, if the shrinkage deformations are constrained by the uneven evaporation and the generated friction between the sub-base and the floor. The value of friction coefficient is depended primarily on the surface roughness of the subbase and the type of polyethylene foil used between the sub-base and the concrete slab. The paper presents the results of experimental investigations on the friction coefficient and the effects of its value on the cracking process of industrial concrete floor...

Utilization of Non-Traditional Fibers for Light Weight Concrete Production

Along with energy savings for heating and cooling, the demand for thermal insulation materials is increasing and is an attempt to achieve good thermal insulation properties for some of the construction materials. In the field of porous and lightweight concrete, this is e.g. concrete for foundations, concrete for floor constructions or flat roofs. The problem with these concrete is a relatively rapid drop in mechanical properties in reducing bulk density, with using conventional silicate binders, especially in the area below 1000 kg/m3. The paper describes the possibility of using recycled organic fibers in combination with lightweight aggregates based on foam glass for the production of porous and lightweight concrete with a good ratio of mechanical and thermal insulation properties.

Nails, tacks, and hinges: the archaeology of Camp Monticello, a World War II prisoner of war camp

ABSTRACT“Provost Marshall General does not concur in the construction of outdoor dance floors at Monticello Internment Camp … Outdoor dance floors would be of no use at an internment camp,” the brigadier general responded to the chief of engineers in 1943. Camp Monticello, located in southeast Arkansas, was an Italian prisoner of war camp constructed according to a set of standardized building plans. Despite the brigadier general’s insistence that Camp Monticello “conform as far as possible to the standard plan,” archaeological research that combines archival research with a metal detector survey shows that the plans were influenced by local politics, access to materials, environmental conditions, and the everyday activities of the prisoners of war.

Study on the leaching performance of chromium (Cr) and cadmium (Cd) from the utilization of solidified nickel slag as concrete floors

With the increasing demands on more metals extraction, the hazardous waste resulted from mining industry has also raised. In this paper, the treatment process of nickel slag containing hazardous metals is described. The treatment involved a solidification process, where nickel slag is used as fine aggregates substituting agent. This study aimed to determine the optimum dosage of nickel slag that met specification in the construction of concrete floors. A series of technical feasibility test were carried out by replacing the weight proportions of sand with nickel slag gradually from 0% to 100% to examine the compressive strength, absorption rate, durability and leaching performance. The results indicated that even though all mixture variations possessed high value of absorption rate indicating high permeability concrete mix, all mixtures, however, had good durability. Furthermore, based on the compressive strength test, a mixture with 60% substitution of nickel slag is considered as a viable replacement of sand in the concrete floors construction in conformance to American Concrete Institute. The leaching performance test showed that leachability of heavy metals content, particularly Cr and Cd from mortar specimens were below the standard according to Indonesian Government Regulation No 101 of 2014, therefore, in terms of environmental point of view, the utilization of solidified nickel is considered safe to be used as concrete floors.

Evaluation of Selected Physicomechanical Properties of SFRC according to Different Standards

Steel fiber reinforced concretes are currently very popular, especially in the construction of industrial floors of warehouses and other halls with relatively large floor areas. However, it is important to mention that despite the rapid development of steel fiber reinforced concretes, the standards and regulations for their designing and testing have not been unified yet. This paper presents findings about the physicomechanical parameters of the steel fiber reinforced concretes manufactured by adding steel fibers into the truck mixer on the building site. The experimentally obtained results from the performed tests of tensile strength in bending according to various procedures are compared, and the suitability of the methods used is assessed according to these procedures.

Industrial technologies of reconstruction of large-panel buildings of the 1-335 series

Technological and constructive decisions of modernization and reconstruction of large-panel buildings of the first mass buildings are considered in the article. The technology of the reinforced concrete diaphragms of the building hardness brings the seismic stability of the building to the normative level. The technologies of erecting a building with bay windows, as well as the construction of attic floors by the method of mounting bulk units enlarged onto the span have been developed. The folding volumetric blocks and the technology of their installation are proposed. The analysis of reconstructive works in two variants showed their rationality and financial attractiveness in comparison with the dismantling of buildings.

Why There Is No Solution to the Palestinian Arab-Jewish Conflict

Why There Is No Solution to the Palestinian Arab-Jewish Conflict Yoav Gelber (bio) The Arab-Jewish conflict resembles a multi-story building. The foundation, deep in the ground, is Muslim perception of Jews as believers of a common religion and not as members of the same nation. The construction of the first floor began with the Zionist migration to the Land of Israel in the late nineteenth century. From the local Arabs’ viewpoint, a religion does not need territory or a nation state. Hence, the Jewish immigration was a colonial project aiming to dispossess the natives. This argument, together with a few other historical narratives, were the core of Arab opposition to Zionism. It was first affirmed by the First Palestinian Congress at Jerusalem in January 1919, and ever since has been the foundation of the Palestinian Arabs’ refusal to accept Israel as a Jewish State and to end the conflict. The second floor was built during the war of 1948. Its first wing was the Palestinian refugee problem. A second one was Jerusalem, divided between Israel and Jordan. A third wing was the armistice lines. Originally, they were bound to be temporary, until permanent borders would be decided in the peace negotiations that were expected to follow. With no peace treaties, they became sacred in the eyes of most of the world. A fourth wing was the involvement of the Arab States. Truly, it had begun earlier, in the late 1930s, but after the defeat of the Palestinian Arabs, and their invasion of Palestine in May 1948, they became the main protagonists who demanded the return of the country to its previous status as an Arab country, against a Zionist, and later an Israeli, demand that the Land of Israel be Jewish as Britain was British and France was French. The Six-Day War added to the building a third floor that was nicknamed with the overall name “the conquest”. One wing of the new floor was united and annexed Jerusalem. The second wave of refugees/emigrants that turned mainly to Jordan and partly continued to the Gulf Emirates [End Page 237] constituted another one. A third wing was the return of the demographic issue. It laid dormant after the war of 1948, but since 1967 it has become a central issue in the Israeli discourse on the future of the territories. During the years, several other layers have been heaped on this floor such as the issue of a Palestinian entity, and whether it should be an autonomy or a fully independent state. In recent years, the settlements, the settlers, and the construction in Jerusalem and the territories have been the current bone of contention. If it had only been worked out the “political process” could be resumed and the conflict would be resolved. Actually, it is just a ripple, irrelevant to the other problems in the lower floors. Beyond “Hello” and “Goodbye”, the word Shalom has in Hebrew two incompatible meanings. One indicates a treaty or an agreement between governments of two states that mutually recognize their sovereignty and borders, have formal diplomatic relations and a certain level of informal connections, and are committed to avoiding war with each other. The second meaning signifies Shalom Al Israel, the peace of the apocalypse, when a wolf will live peacefully with a sheep and a leopard will lie back with a young goat. In modern language: a peace in which Jews and Arabs will befriend each other over Hummus in Damascus or in Tel-Aviv. A peace in the first sense between Israel and some Arab States is possible under certain circumstances. The war of 1973 created the necessary conditions for a peace between Egypt and Israel. Hussein’s decision to detach Jordan from the West Bank and its Palestinian inhabitants paved the road for an Israeli-Jordanian peace treaty. However, these are agreements between governments. Peace in the second meaning does not exist among the Arabs, all the more so it cannot be accomplished between them and Israel. The Palestinians are a different case, and cannot have peace with Israel even in the first meaning. Their conflict is not one between states but a...

Measures to reduce construction time of high-rise buildings

The organizational and technological solutions for high-rise buildings construction efficiency increase are considered, primarily – decrease of typical floor construction time and improvement of bearing structures concrete quality. The essence of offered technology is: a concrete mixing station and a polygon mainly for load-bearing wall panels with starter bars casting are located on the building site; for reinforced concrete components manufacturing and butt joints grouting the warmed-up concrete mixtures are used. The results of researches and elaborations carried out by the SPSUACE in area of a preliminary warming-up of concrete mixtures are presented. The possibility and feasibility of their usage in high-rise buildings and of excess height buildings construction including cast-in-place and precast execution are shown. The essence of heat-vibro treating of concrete mixture is revealed as a kind of prior electroresistive curing, and the achieved results are: accelerated concrete strength gain, power inputs decrease, concrete quality improvement. It is shown that the location of a concrete mixing station on the building site enables to broaden possibilities of the “thermos” method use and to avoid concrete mixtures warming up in medium-mass structures erection (columns, girders) during the high-rise buildings construction. It is experimentally proved that the splice between precast elements encased with warmed-up concrete mixture is equal with conjugated elements in strength.