Drop Panels Research Articles

Comparison of Seismic Performance of Buildings with Conventional Slab and Flat Slab in Different Zones of Bangladesh

As usable land is scarce in Bangladesh, the demand for high-rise buildings has risen over the past few decades. Conventionally, reinforced cement concrete (RCC) structures in Bangladesh have been used for residential, educational, institutional & commercial purposes. Bangladesh is located in a relatively earthquake-prone region on the fault plane; it is of utmost importance to assess seismic conditions while constructing a structure. Three types of slabs have been analyzed: conventional RCC slab, flat slab with drop panel, and flat slab with drop panel & shear wall. Typically, a conventional RCC slab contains a beam, column & slab with a large thickness of the beam. To avoid this, a flat slab with a drop panel may be used, but it has some limitations. As it has no lateral support, a flat slab with a shear wall can be replaced to gain more stability. According to BNBC 2006, Bangladesh was divided into three seismic zones. However, according to BNBC 2020, it is revised into four seismic zones. Seismic comparisons of three models in four seismic zones have been conducted. Maximum story displacement, maximum story drift, overturning moment and story shear have been found after analyzing three different types of models located in different seismic zones. The maximum story displacement and maximum story drift for flat slabs are greater than conventional slabs and flat slabs with shear walls. Moreover, the displacement between conventional and flat slabs with shear walls varies a little. Maximum overturning moment and story shear: it appears that for the traditional slab, the value is maximum, the flat slab is minimum, and the flat slab with the shear wall is between those two. The model for flat slab has been found to be more flexible than conventional RCC slab and flat slab with the shear wall.

COMPARATIVE STUDY OF FLAT SLAB DESIGN USING VARIOUS INTERNATIONAL CODES

The structural function of beamless floor system is to collect the gravity load and other load such as wind load etc. and to transfer to the vertical structural elements i.e. column through the combined capacity in flexure and shear. In Flat slab, the slab is directly supported on the columns. Moments and shear values are usually the largest over the columns. However, when spans are relatively small and imposed load is low, the thickness of slab can be increased to reduce the stresses at slab-column joint which would result in providing greater effective depth for negative moments occurring near the column. With increasing span and live load intensity, the thickness requirement increases which does not give economical solution. So, to tackle this problem flaring of the column at top is done such that the plan geometry at the column head is similar to that of the column. The column capital is intended primarily to increase the capacity of the slab to resist punching shear. The column capital stiffens the slab, which help in controlling the floor deflection. Thus, the floor span can be increased to some extent. Beyond a certain range of span, further stiffening of the slab is required which is achieved by increasing the slab thickness of the slab panel around the column capital. This portion of the slab is known as drop panel. For flat slabs and flat plates supported directly by columns, shear may be the critical factor in design. In almost all tests of such structures, failures have been due to shear or perhaps shear and torsion. These conditions are particularly serious around the exterior columns. In the present study, attempt has been made to understand different methods of analysis of flat slab and parameters, which governs the design parameters of the flat slab. Attempts have been made to study the provisions of flat slab in well-known international standards such as ACI 318, EC-2 and IS 456:2000. Keywords: Flat slab, drop panel, Column head, IS 456:2000, ACI 318, EC-2

Investigation of the Influence of Drop Panels on Natural Period of Vibration of Flat Slab Building Structures

Investigation of the Influence of Drop Panels on Natural Period of Vibration of Flat Slab Building Structures

Stiffness, Vibration, and Strength of Flat Slab and Flat Plate Lightweight Concrete Slabs

Flat slabs made of two-way reinforced concrete are a common, effective, and affordable structural method. Thin layer slabs and lightweight are of great importance in modern building construction without the need to increase the cross-section of columns, walls, and foundations. Consequently, it becomes more important to cover all aspects related to stiffness, vibration, and strength of lightweight concrete slabs. To achieve serviceable flat slabs from lightweight concrete (LWC), the comparison between LWC flat plate and flat slab is studied in this article for strength and stiffness. The construction of the flat plate is much easier than other slabs even though the problem facing the flat plate is the punching shear. Hence, the addition of the drop panel as a solution. However, the two LWC slabs are exposed to a uniform pressure of dead load and human live load. The vibration of the slab is related to the stiffness in the form of the natural frequency. These floor systems should satisfy walking excitation criteria of acceleration limit , which is equal to 0.50% of g for office occupancies. This study aims to analyze a flat plate and flat slab with a drop panel for strength and stiffness. The analysis is carried out in ABAQUS software. The results of the analysis show that the flat slab has an effective increase in strength of about 60% compared to the stiffness which was lower by about 2.2 %. However, the stiffness of both slabs is within the limits of walking excitation criteria.

Application of evolutionary algorithms to design economic flat slab buildings based on the intended function

Numerous studies revealed optimization techniques' applicability in minimizing the costs of reinforced concrete buildings. However, the existing literature has narrowly focused on optimizing buildings with a single function, such as residential or office buildings, hindering the generalization of the results. This paper aims to bridge the gap between optimization and structural engineering by obtaining the minimum-cost design of flat slab buildings with different intended functions. In this context, the optimal designs of 120 alternatives were obtained, considering various spans (4–8 m), live loads (2–10 kPa), and concrete compressive strength (25–40 MPa). The optimization was executed using the evolutionary algorithm provided in Microsoft Excel’s Solver tool. The optimization model permits the utilization of drop panels to resist punching stresses developed from the slab-column interaction. The objective function is the cost of materials and labor involved in constructing floors and columns. The decision variables are the floor dimensions and column configurations in dimensions and reinforcement. The structural constraints were applied per the Egyptian design code (ECP203-2020). Eventually, guidelines were developed to help the designers choose the economic floor system and quantities of materials based on the building's intended function.

ANALYSIS OF PENEL DROP-OFF ON SHEAR SLIP AT FLAT SLAB IN THE ANIMAL HOSPITAL EDUCATION BUILDING OF THE FACULTY OF VETERINARY MEDICINE (RSHPFKH), UDAYANA UNIVERSITY

The Animal Hospital Education of the Faculty of Veterinary Medicine (RSHP-FKH) at Udayana University is located on Sesetan Main Road, Markisa Alley, No. 6, South Denpasar District, Denpasar, Bali. The building structure is planned with a modified flat slab design incorporating drop panels around the column areas. The purpose of this modification is to provide flexibility in spatial arrangement, facilitate the installation of mechanical and electrical systems, and indirectly meet the height requirements specified by the local regulations in Bali. The structural analysis of the Animal Hospital Education building at RSHP-FKH, Udayana University was conducted using the ETABS v.18 software, following the guidelines of the Indonesian National Standard (SNI). The analysis focused on the effect of drop panels on shear slip in the flat slab. The analysis aimed to determine the magnitude of deflection and its corresponding locations in the structure. The results of the analysis provide relevant information regarding the strength and stability of the building structure, ensuring that the RSHP-FKH building at Udayana University meets the established standards.

DEFLECTION OF FLAT SLAB-DROP PANEL IN THE G2 BUILDING AT WARMADEWA UNIVERSITY

To conserve building height, flat slabs are concrete structures that do not employ beams as weight transfer to columns. The flat slab system structure is prone to shear collapse due to the lack of beams. A column head is made to forward the load from the plate to the column so that the shear value in the building is not too high. This is done by expansion at the end of the column or by thickening around the critical circumference of the column and plate meeting. The Warmadewa University G2 Building Planning Analysis is carried out during the planning stage, using a flat slab-drop panel structural system as one of the optional structural systems that can be used to obtain a building height that is in accordance with Bali Provincial Regulation Number 16 of 2009 concerning the regional spatial plan of the Province of Bali. Terompong street No. 24, Sumerta Kelod, East Denpasar sub-district, Denpasar City, Bali, is where the Warmadewa University G2 building will be built. According to the soil data, the building is constructed on a medium soil site class with a building structure risk level IV. The Warmadewa University G2 Building structure was studied using etabs v.18 software in accordance with SNI 2847-2019 requirements for structural concrete for building buildings and loading in accordance with SNI 1727-2020 criteria. The biggest deflection value occurs in the middle lane due to the load from the function room, as determined by the study for the dimensions of the 350mm thick drop panel and 250mm thick slab utilizing a column size of 600 x 600 mm with a span of 8000mm. The inner drop panel experiences the highest lateral loads due to shear failure.

Experimental study on the collapse response of flat slab structures with drop panels under gravity loading condition

This paper presents the results of an experimental study on the collapse behavior of two reinforced concrete flat slab assemblies with drop panel connections subjected to uniformly distributed loads applied through 24 loading points. The two tests, named MC and PC, simulated local failures at mid-span columns and penultimate columns, respectively. Both assemblies exhibited elastic behavior until cracking values were reached, followed by degradation of stiffness due to crack development beyond the elastic zone and a long plateau near collapse. The main differences between the assemblies were the higher collapse load of the MC assembly, attributed to slab additional slab extension surrounding two test panels, and the load redistribution pattern. Both assemblies showed ductile behavior in the inelastic region, with large deformation capacity allowing tensile membrane action to mobilize. The collapse modes observed were the failure of the outer compressive ring and the tearing out of tension slab reinforcement from the concrete. The traditional yield-line method may not be suitable for quantifying the collapse resistance of this type of structure, and numerical simulations are suggested for this purpose. The experimental data from these tests, as well as previous tests, could be valuable for validating simulation models.

Design Modification of Klandasan Parking Building Using Flat Slab with Drop Panel And Shear Wall Method

The Klandasan Parking Building (GPK) is an 8-story parking built in Balikpapan that serves as vehicle parking and uses a conventional structure system (columns, beams, plates) where the highest beam is about 800 mm. To maximize the clearance of each story, an alternative structure system is planned by removing beams called flat slabs. The new plan is conducted by modifying the structure into a dual system which consists of an Intermediate Moment Resisting Frame, a flat plate with drop panels used to withstand gravitational loads on buildings and a Structural Wall System (SWS) installed to resist lateral loads such as earthquake and wind. Structure’s plan refers to SNI 03-2847-2013 and SNI 03-1726-2012 which are Indonesia’s concrete and earthquake codes respectively. In addition, PPURG 1987 is also used to determine loads for the building. The analysis result shows that the building could be changed from 8 to 9 stories using the same total height of 8 stories. The depth of plates and drop panels which are supported by interior and exterior columns are 250 mm and 100 mm respectively. Turning to the shear wall, a thickness of 350 mm can be used to resist lateral loads.

Efficiency of shear studs manufactured from threaded bars on the punching behavior of flat slabs

Punching resistance in flat slab systems in reinforced concrete structures is often provided with drop panels or shear reinforcement around columns. Shear studs are effectively used in these structures as shear reinforcement. However, factory-made shear studs may not be available in all locations and small quantities for small projects. Therefore, cheap shear studs that can be manufactured from widely available materials in small quantities can be very useful in certain cases. In this study, shear studs manufactured from threaded bars, widely available in hardware stores, are used for providing punching resistance to flat slabs. Stud heads were formed with T-section nuts. Four slab specimens, two with shear studs and two without, were cast and tested under concentrated loads at their mid-point. The slabs had 2150×2150×150 mm dimensions and they were cast with two different longitudinal reinforcement ratios. Test results showed that manufactured shear studs significantly increased the load and deformation capacities of the slabs. Slabs with shear studs were able to show up to three times higher bending deformations and they were able to sustain up to 50% higher loads. The study has shown that these studs can be effectively used for punching strengthening purposes in flat plate systems or in other cases where punching resistance is needed.

Punching shear behaviour of steel-concrete composite slab-column connections with spatial steel drop panel

The punching behaviour of a slab-column connection with a spatial steel drop panel composed of a steel drop plate, batten plates and a confined steel plate were experimentally investigated in this study. The experimental variables were the size of steel drop plate, the length of batten plate and whether the steel drop plates have slits. Five specimens were manufactured and tested under monotonically-increased load to ascertain the effect of different details of the spatial steel drop panel components on the punching shear performance. Test results showed that configuring the spatial steel drop panel improved the punching failure range of the slab, and led to the increase of punching strength and ductility of the slab-column connection. A formula, which calculates the punching shear capacity of a slab-column connection with a spatial steel drop panel, was proposed and the calculated results are in good agreement with the test results.

Punching and post-punching shear failure behaviors of laterally-restrained and eccentrically loaded flat plate slab-column joints with drop panels

In concrete flat plate slab-column joints with drop panels, successive punching shear failures often occur at the slab-drop panel interface and along the column perimeter. When such joints are subjected to combined bending-shear actions under an eccentric load, their punching and post-punching shear failure behaviours are further complicated which can significantly impact the progressive collapse behaviour of the structural system. An experimental study was conducted on six laterally-restrained slab-column joint specimens with drop panels. Different levels of load eccentricities and different drop panel thicknesses were considered. Two punching shear failure sections were also identified. For a thick drop panel, the first punching failure took place at the slab-drop panel interface, followed by the second punching shear failure occurring along the column perimeter. For a thin drop panel, on the other hand, punching shear failure only occurred at the column perimeter. The damage patterns, the reinforcement strains and the joint strengths before and after punching failure at two different sections were analysed. Numerical simulation was conducted to investigate the effects of load eccentricity on the inclination of the punching cone. Numerical results showed that the punching cone angles at the slab-drop panel interface and at the column perimeter are, on average, 11.6° and 27.1°, respectively. In addition, larger eccentricity contributed to higher cross-sectional shear stresses on the eccentric loading side, leading to reduced punching shear strength and earlier damage. Furthermore, the experimental and numerical punching shear strengths were compared against the predictions of the Chinese, American and European design codes. Finally, a post-punching strength prediction method was proposed, and the predicted strengths deviated from the experimental results by −16% and 23%, for the thick and thin drop panels, respectively. In addition, the integrity reinforcement was also found to contribute at least 80% to the post-punching shear strength.

Structural Design Optimization of Flat Slab Hospital Buildings Using Genetic Algorithms

The construction costs of hospital buildings are relatively high due to the need to fulfill their complex functions and avoid mishaps. In this context, this study aims to minimize the total construction costs of hospitals while still satisfying the special architectural, practical, and structural requirements specified by design codes. To this end, 48 design alternatives with two floor systems (flat slabs with and without drop panels), three column spacings, and eight concrete grades were optimized using genetic algorithms provided by Palisade Evolver. The objective function included the materials and labor costs per square meter of the floor plan. The decision variables involved the concrete dimensions and steel bars of floors and columns. The hospital buildings were subjected to gravity, earthquake, and wind loads to thoroughly examine the realistic loading conditions. The design was performed in accordance with the Egyptian code for the design and construction of concrete structures and the Egyptian guidelines for hospitals and healthcare facilities. The results revealed that using low-strength concrete, and flat slabs without drop panels could achieve the best design. The slab thickness had a governing impact on the total cost of both floor systems.

Experimental and analytical analysis of punching shear in flat slabs supported on column topped with concrete head

An experimental laboraatory test of the two series of slab-column elements topped with drop panels of varying sizes is described in this paper. The scope of the paper is to investigate the influence of the drop panel size and stiffness on the behaviour of the connection between the flat slab and the column topped by the concrete head. The impact of the head size and stiffness is analysed analytically and experimentally. The experimental test results show that at a ratio hsh/lsh≤0.55 the heads are too flexible to cause punching shear outside the head, confirm significant concentrations of shear forces at the corners of the large support, and show a significant contribution of the linear parts of the control perimeter to the ultimate force transmitted by the slab-column joint. The authors compare the experimental test results with the considered standard calculation methods and indicate the correlations. The paper provides new experimental results and proposals for the application of a reduction factor for permissible shear stresses in the EC2 standard that depends on the dimension of the support. Simultaneously, the experimental results and the comparison with the standard calculations indicate a further need for research on the connection of a slab to a column topped by a drop panel.

The design of the flat slab system with drop panel in the Sukawati market building

Sukawati Market Building has 4 floors and 1 basement with a total building area of 1136.16 m2. It was designed to use a flat slab structure system with the addition of drop panels that maintained the height or story clearance while reducing total building height by eliminating the interior beams. The structure was designed follow the Indonesian Standard for reinforced concrete building design guideline and assessed through finite element simulation. The shear capacity of the flat slab was determined by the strength of the concrete and its dimensions. The reinforcing bar of flat slabs with drop panels is determined in the same way as the reinforcing bar of concrete slabs. Based on the results, the design efficiently resists the forces demand while meeting the deflection requirement, reflecting the structure system's safety and serviceability. The structure system also maintains the total height of the building in order to comply with local high-limit regulation.

Lateral Behavior of Slab-Column Connection with Pyramid Shaped Drop Panel

Both experimental and finite element analysis (FEA) were used to study the interior slab-column connections made with pyramid-shaped drop panels subjected to vertical and horizontal loads. The dimensions of the models at

Design Analysis of Commercialized Building using Non-Identical Slab Arrangements

Abstract: Analysis and design of buildings must take earthquakes into account. Analyzing how a structure will react to a given set of loads is called structural analysis. Design is the process of determining the structure's proper parameters. It would take a long time to do structural analysis and design by hand. Any building may be easily analysed and designed with the help of software. The goal of this research and design study is to compare and contrast four common commercial building slab configurations—the conventional slab, the flat slab with drop panels, the grid/waffle slab, and the structure with a load bearing wall. At get to the results, a study was run in STAAD to analyse the impact of varying pressures on two different slab designs. The cutting edge of computer programming. The IS-1893:2002 standard mandates the incorporation of seismic forces. We used IS-456:2000 to determine how wide, tall, and deep to make the beams, columns, and slabs. IS-875:1987 (Parts 1 and 2) specifies the requirements for applying load combinations, dead loads, and imposed loads (Parts 3 and 5). (Part 5). Wind speeds of 55 metres per second and an earthquake zone of 5 will be employed as criteria in the next research. The results of a research comparing the displacements, moments, shear forces, and axial forces in two different slab pattern structures are shown using bar charts. Data is presented in the form of tables and bar charts. In general, the greater the number of stories, the greater the amount of movement between floors. Buildings using grid slabs performed better in the examination of the building's resistance to wind and seismic loads, and they were also shown to be more cost-effective

Parametric Analysis of Flat Slab with Shear Wall Lateral Resisting System Subjected to Dynamic Loading

Abstract: In the present project 20 storey structure is modelled using ETABS and loadings are considered as per IS codes. The models were analysed for both static and dynamic time history analysis the results are extracted, graphs are plotted. Models were compared and conclusions are drawn. The conclusions drawn from the analysis are, The Static analysis and dynamic analysis are having different values and time history analysis seems to be more accurate due to consideration of modal analysis and sitespecific analysis. The displacement is the main parameter in terms of serviceability criteria, the time history analysis shows lesser values than static analysis. It indicates that the static analysis may be on higher side for high rise structures. The comparatively huge displacement in case of Model M02 for both static and dynamic analysis proves the flat slab structure without drop panel and shear wall is not acceptable for lateral loading. From the overall analysis, it is found that the Column beam system with shear wall is best system to adopt, however in case of project demand, it is better to adopt flat slab drop panel system with shear wall located at centre as preference. In case of difficulty of shear wall at centre, the shear wall at corners can be adopted.

Analisis Riwayat Waktu Nonlinier Struktur Flat Slab dengan OpenSees Navigator

Structural systems that do not use a beam as the main component were first developed by Turner in 1906. This structural system is better known as a flat slab. The flat slab structure is supported by column heads and drop panels, or without drop panels, or without column heads. Several building codes such as IS 456: 2000, ACI 318-08, ACI 318-19, EC 2:2004, and NZS 3101 (Part 1):2006 provide guidance for designing flat slab systems under gravity loads only. However, many flat slab buildings are also built in areas with high earthquakes which can cause the collapse of buildings due to earthquake loads. In this paper the 10-level flat slab building structure design results are analyzed using nonlinear time history response analysis with the help of OpenSees Navigator software using several earthquake records, namely Kobe (Japan, 1995), Imperial Valley (California, 1979) and Tabas (Iran, 1978) which has been adjusted to the design spectra of the city of Yogyakarta. From the results of the analysis using OpenSees Navigator, it was found that the story drift that occurred was still within the limits required in the regulations, so that the building being reviewed was still within the limits of life safety design.

Pre- and post-punching failure performances of flat slab-column joints with drop panels and shear studs

To investigate the pre- and post-punching failure performances of flat slab-column joints with drop panels and shear studs, static loading tests were conducted on three joint specimens subjected to in-plane restraints. The pre- and post-punching failure modes and load capacities of the joints were analysed. The tests identified successive punching failures at two critical regions (column perimeter and slab-drop panel interface) in all three joints. Compared with the specimen with a drop panel only, installing shear studs within the drop panels contributed to improving the punching shear strength. Although the post-punching capacity was not significantly improved, utilisation of shear studs effectively increased the ductility of the joints, rendering the punching failure around the column area more ductile. Punching shear strength validation against the international design codes reveals that they were conservative for the specimen with a drop panel only but overestimated for specimens with drop panels and shear studs.