scholarly journals INDICATORS OF FLOOR SLABS REINFORCEMENT TECHNICAL AND ECONOMIC INVESTIGATION BY DIFFERENT TECHNOLOGIES

2018 ◽  
Vol 1 (50) ◽  
pp. 253-262
Author(s):  
O. S. Molodid
Keyword(s):  
Carbon Fiber ◽  
Concrete Slab ◽  
Steel Plates ◽  
Reinforced Concrete Slab ◽  
Floor Slabs ◽  
Metal Plates ◽  
External Reinforcement ◽  
Cost Of Materials ◽  
The Cost ◽  
Technical And Economic Indicators

The paper presents the results of technical and economic indicators study of reinforcing monolithic reinforced concrete slab various methods, namely: the supply of metal beams with the installation of additional supports, external reinforcement of stretched zones using MAPEI technology, adhesion of metal plates and carbon fiber to the developed technology. There is established that the highest indicators of the materials cost, labor intensity and wages for the execution of works relate to the option of reinforcing the floor slab by supplying metal structures, and the lowest indicators have options for reinforcing the floor slabs using MAPEI technology and bonding carbon fiber under the developed technology. The cost of materials for reinforcing the plate in the developed technology with the adhesion of steel plates is the lowest, but complexity, wages and the duration of the work on this technology are much higher than other studied technologies of external reinforcement.

scholarly journals Research of technical and economic indicators of reinforcement of reinforced concrete beams by different technologies

2020 ◽  
pp. 144-153
Author(s):  
О. Molodid ◽  
I. Maksymiuk ◽  
A. Hryhorova
Keyword(s):  
Carbon Fiber ◽  
Bearing Capacity ◽  
Fiber Reinforcement ◽  
Economic Indicators ◽  
Design Solution ◽  
Labor Intensity ◽  
Rigid Support ◽  
Carbon Fiber Reinforcement ◽  
External Reinforcement ◽  
Technical And Economic Indicators

The article presents the results of experimental investigations to determine the destructive force of beams reinforced with external reinforcement and control (without reinforcement). According to the results of such investigations, it can be stated that the strengthening of beam structures by external reinforcement made it possible to increase their bearing capacity by 383.3%. It has been established that both carbon fiber reinforcement using "clamps" and carbon fiber reinforcement are effective.The performed analytical researches established technical and economic indicators of various methods of reinforcement of beam constructions, namely: the addition of additional supports, the addition of additional beams, the external reinforcement of stretched zones by MAPEI technology. As a result, data were obtained indicating that the reinforcement of the crossbar by bringing additional rigid support requires 110.4 man-hours (100%), the reinforcement of the crossbar by bringing additional beams - 94.4 man-hours (85.5%), the reinforcement of the crossbar by external reinforcement - 48 man-hours (43.5%). In this case, the reinforcement of the crossbar by bringing additional rigid support is performed in 9.7 days (100%), the reinforcement of the crossbar by bringing additional beams - 6 days (62%), the reinforcement of the crossbar by external reinforcement - 4 days (41.4%). It is also established that the reinforcement of the crossbar by bringing additional rigid support costs 51.8 thousand UAH (100%), strengthening the structure by bringing additional beams - 58.1 thousand UAH (112%), strengthening the structure by external reinforcement - 35.72 thousand UAH (68.9%).The obtained research results indicate that the labor intensity, duration and cost of reinforcing the beam with external reinforcement is lower compared to other technologies. Efficiency is achieved by a structural component - increasing the bearing capacity without changing the design solution and by technological component - reducing the labor intensity, duration and cost of work.

scholarly journals MUD-CONCRETE SLAB SYSTEM FOR SUSTAINABLE CONSTRUCTION

2021 ◽  
Author(s):  
R.R. Jayasinghe ◽  
◽  
K.I.U. Nanayakkara ◽  
F.R. Arooz ◽  
R.U. Halwatura ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Global Climate ◽  
Sustainable Construction ◽  
Modular Construction ◽  
Reinforced Concrete Slab ◽  
Concrete Shell ◽  
Concrete Filling ◽  
Doubly Curved ◽  
The Cost

The urgency of global climate emergency has drawn significant attention to the building industry over the last few years. Today, the building sector is responsible for 38% of the world’s greenhouse gas emissions, according to UNEP. 60% -70% of embodied carbon in a conventional column-beam reinforced concrete building is in its floor system. This paper discusses the possibility of constructing an earthen slab system using mud-concrete. It investigates a doubly curved shell structure, working predominantly in compression, to fulfil both environmental and economical demands in the construction industry; reducing the cost and labour expenses nearly 50% compared with that of traditional reinforced concrete slab systems. A 1 m x 1 m prototype mud-concrete slab was constructed to check the potential for modular construction with a square footprint. Poured mud-concrete shell of 50 mm thickness is the primary structural component, while a non-structural mud-concrete filling to a horizontal level 50 mm from apex was used to create a usable floor surface. Masonry mould method was used as the formwork system for the construction considering its cost effectiveness and ease of construction.

scholarly journals Optimal Design of Steel–Concrete Composite Beams Strengthened under Load

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4715
Author(s):  
Piotr Szewczyk ◽  
Maciej Szumigała
Keyword(s):  
Numerical Models ◽  
Concrete Slab ◽  
Plate Thickness ◽  
Steel Part ◽  
Composite Beams ◽  
Steel Plates ◽  
Reinforced Concrete Slab ◽  
Recoverable Strain ◽  
Bending Capacity ◽  
Optimum Solution

This paper presents results of numerical analysis and experimental research on strengthening of steel–concrete composite beams. Studied members consisted of IPE200 I-beam and 90 × 700 mm reinforced concrete slab. The steel part of the section was strengthened by welding additional steel plates at the bottom. The study was performed for plate thickness ranging between 6 to 22 mm. Spatial FEM models were developed to account for material and geometric nonlinearities and for stress and post-welding strain. Proposed numerical models were experimentally validated. One aim was to find an optimum solution which would minimize cost and maximize bending capacity. To achieve this, energy parameters available in numerical simulations were reviewed and analyzed. Recoverable strain energy value determined in Abaqus was used to find the optimum solution.

Design and Construction of a Precision Weighing Lysimeter in Southeast Colorado

2018 ◽  
Vol 61 (2) ◽  
pp. 509-521 ◽  
Author(s):  
Allan A. Andales ◽  
Dale Straw ◽  
Thomas H. Marek ◽  
Lane H. Simmons ◽  
Michael E. Bartolo ◽  
...  
Keyword(s):  
River Basin ◽  
Concrete Slab ◽  
Ground Surface ◽  
Load Cell ◽  
Steel Plates ◽  
Reinforced Concrete Slab ◽  
Arkansas River ◽  
Undisturbed Soil ◽  
Design And Construction ◽  
Weighing Lysimeter

Abstract. Accurate estimates of crop evapotranspiration (ET) are needed to effectively manage irrigation resources in the Arkansas River basin in Colorado and to maintain compliance with the Arkansas River compact with Kansas. This was a major impetus for the construction of a precision weighing lysimeter in the Arkansas River basin at the Colorado State University (CSU) Arkansas Valley Research Center (AVRC) near Rocky Ford, Colorado. The objective of this article is to describe the design and construction of the weighing lysimeter and characterize its performance and unique features. The main components of the lysimeter facility are the foundation, the scale system, the soil monolith tank, and the outer tank that houses the aforementioned components. The foundation, which was 4.12 m below the ground surface, consisted of a reinforced concrete slab 2.00 m wide by 6.31 m long and 0.20 m thick that was anchored to six square shaft helical anchors. The outer tank was secured onto the foundation and had a rectangular floor area of 6.10 m × 1.79 m (10.92 m2), an interior vertical clearance of 2.15 m, and walls made of reinforced 8 mm thick steel plates. The floor scale system (mechanical levers and load cell) was installed inside the outer tank and had a gross capacity of 17 Mg. The monolith tank (1.50 m × 1.50 m area, 2.44 m depth, 10 mm steel walls) containing an undisturbed soil profile was set on the scale system. The lysimeter facility was installed in the middle of a 3.5 ha field. Calibration of the scale system resulted in a linear response (R2 = 1.000), with an equivalent conversion coefficient (slope) of 151.09 mm H2O (mV V-1)-1. The sensitivity of the scale system was 0.023 mm of water, which is sufficient for measuring diurnal (15 min to hourly) changes in ET and soil water. Load cell readings taken at a frequency of 0.5 Hz were averaged in 15 min intervals (450 readings per 15 min) to filter out the measurement noise that was attributed to wind. The lysimeter was found to adequately detect ET, irrigation, and precipitation perturbations with an actively growing alfalfa hay crop ( L.) in 2011. The lysimeter facility is a state-of-the-art tool for quantifying ET of irrigated crops in the lower Arkansas basin in southeast Colorado. Keywords: Calibration, Evapotranspiration, Load cell, Weighing lysimeter.

scholarly journals Improving the manufacturability of floor slabs by pre-installing elements that partially replace reinforced concrete and formwork

2021 ◽  
Vol 258 ◽  
pp. 09019
Author(s):  
Seyran Akimov ◽  
Olga Balakchina ◽  
Elvira Akimova ◽  
Vladimir Malahov ◽  
Vasilij Shalenny
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Expanded Polystyrene ◽  
Simultaneous Increase ◽  
Resource Saving ◽  
Reinforced Concrete Slab ◽  
Floor Slab ◽  
Subsequent Performance ◽  
Permanent Formwork ◽  
Floor Slabs

The article discusses well-known and perspective constructive and technological systems for the installation of monolithic and precast-monolithic floor slabs of civil and industrial buildings. It shows examples and expediency of using all kinds of inserts made of plastic and other light materials and products for replacing a part of heavy monolithic reinforced concrete. An original resource-saving method for the installation of precast-monolithic floor slabs with a simultaneous increase in the degree of their construction readiness is proposed. This effect is achieved by reducing their own weight and the use of permanent formwork. Reduction in own weight of the precast-monolithic floor slab is ensured by the use of volumetric lightweight trapezoidal or rectangular inserts, preferably made of expanded polystyrene, during its installation. The use of permanent formwork will eliminate the need for the subsequent performance of labor-intensive finishing and insulation works. To confirm the effectiveness of using the proposed method of precast-monolithic floor slab installation, the operation of two floor slabs was modeled in the LIRA SAPR computing complex - the proposed reinforced concrete innovative slab and a solid reinforced concrete slab. Having analyzed the calculated forces, deformations and the corresponding consumption of reinforcement and concrete, comparative indicators were obtained for the proposed innovative slab and for a typical solid floor slab. As a result, significant savings in material and cost have been proven.

scholarly journals NUMERICAL STUDIES OF THE COEFFICIENT OF THE DEGREE OF PINCHING OF HOLLOW-CORE PRECAST SLABS IN STONE WALLS

2019 ◽  
Author(s):  
V. Derkach
Keyword(s):  
Elastic Modulus ◽  
Reinforced Concrete ◽  
Numerical Calculation ◽  
Concrete Slab ◽  
Hollow Core ◽  
Pinch Point ◽  
Reinforced Concrete Slab ◽  
Numerical Studies ◽  
Floor Slabs ◽  
Stone Walls

The results of numerical studies of the degree of pinching of hollow-core precast slabs in the stone walls in the environment of the computing system ANSYS are presented. The numerical calculation of the junction of the floor slab joints with the bearing wall was carried out by the finite element method taking into account the contact interaction of the floor slabs with masonry. The theoretical values of the pinch point degree coefficient are compared with the results of physical studies of a fragment of reinforced concrete slab of prestressed multi-core hollow-core forged slabs with platform joints. The difference between the theoretical and experimental values of the degree of pinching did not exceed 12.5. Based on the numerical calculation, the dependences of the coefficient of the degree of pinching from the elastic modulus of the masonry guests and the magnitude of the compression stresses of the load-bearing walls, using which you can calculate the value of the reference bending moments arising in the floor slabs are obtained. It is shown that the coefficient of the degree of pinching K non-linearly increases with an increase in the elastic modulus of masonry bearing walls. In this case, the greatest influence on the values of K has a change in the modulus of elasticity in the range of 1200-6000 MPa. In the case of supporting the slabs on the walls, made of aerated concrete blocks through a monolithic reinforced concrete belt, the value of the coefficient K increases 1.5 times. It has been established that the degree of pinching depends nonlinearly on the level of compressive stresses at the contact of the plate with the wall. At high levels of compression equal to 1-2 MPa, which are characteristic of the walls of the lower floors of multi-storey buildings, the value of the degree of pinching is in the range of 0.65-0.81.Приведены результаты численных исследований коэффициента степени защемления многопустотных железобетонных плит в каменных стенах в среде вычислительного комплекса ANSYS . Численный расчет узла сопряжения плит перекрытия с несущей стеной выполнялся методом конечных элементов с учетом контактного взаимодействия плит перекрытия с каменной кладкой. Выполнено сопоставление теоретических значений коэффициента степени защемления с результатами физических исследований фрагмента железобетонного перекрытия из предварительно напряженных многопустотных плит безопалубочного формования с платформенными стыками. Разница теоретических и экспериментальных значений коэффициента степени защемления не превысила 12,5 . На основании численного расчета получены зависимости значений коэффициента степени защемления от модуля упругости каменной кладки и величины напряжений обжатия несущих стен, с помощью которых можно рассчитать величину опорных изгибающих моментов, возникающих в плитах перекрытия. Показано, что коэффициент степени защемления К нелинейно возрастает с увеличением модуля упругости каменной кладки несущих стен. При этом наибольшее влияние на значения К оказывает изменение модуля упругости в диапазоне 12006000 МПа. В случае опирания плит перекрытия на стены, выполненные из ячеистобетонных блоков, через монолитный железобетонный пояс значение коэффициента К возрастает в 1,5 раза. Установлено, что коэффициент степени защемления нелинейно зависит от уровня сжимающих напряжений по контакту плиты со стеной. При высоких уровнях обжатия, равных 12 МПа, которые характерны для стен нижних этажей многоэтажных зданий, значение коэффициента степени защемления находится в диапазоне 0,650,81.

A Parametric Study of the Reinforced Concrete Slab Subjected to Dynamic Excitation

2011 ◽  
Vol 147 ◽  
pp. 270-277
Author(s):  
Saddam M. Ahmed ◽  
Gunasekaran Umarani ◽  
Gregory A. MacRae
Keyword(s):  
Parametric Study ◽  
Concrete Slab ◽  
Element Model ◽  
Load Resistance ◽  
Analytical Investigation ◽  
Reinforced Concrete Slab ◽  
Analysis And Design ◽  
Yield Line Theory ◽  
Floor Slabs ◽  
Lateral Load Resistance

The width of effective slab to estimate the beam flexural strength at the beam ends in structures subjected to lateral loading, such as earthquake, is not explicitly addressed in design codes. As a result, designers often ignore the contribution of floor slabs to the lateral load resistance. There is a need for a simple model to assess the slab contribution to beam strength for analysis and design. General expressions for the yield loading and stiffness characteristic of the slab element have been developed which is more sensitively depend on yield line theory beside other parameters such as spacing, yield strength, area of reinforcement, and the span length. A model considering beam growth, bending effects and the slab effect is being considered in the present work. The results of the analytical investigation are compared with experimental results. The slab element model is then used to conduct a parametric study aiming to investigate the effect of the distribution and strength of the slab steel. It is shown that the performance of the unit is directly related to this steel.

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