Voided Slab Research Articles

PERENCANAAN JEMBATAN PENYEBERANGAN ORANG DENGAN STRUKTUR BAJA CASTELLATED DAN STRUKTUR BETON PRATEGANG VOIDED SLAB (Studi kasus Kawasan Industri Rembang Pasuruan Jl. Raya Surabaya-Pasuruan Km 50, Raci, Pasuruan)

The existing traffic conditions at the gate of Pasuruan Industrial Estate Rembang (PIER) located on Surabaya-Pasuruan Highway KM 50, Desa Raci, Bangil, Pasuruan is classified the National Highway type II class 1. It has an average volume of 286 pedestrian / hour (V) and 5175 vehicle / hour (P), so PV2 value is equal to 7.66 x 109. It can be a traffic accident-prone area, especially for pedestrians. Therefore, it needs the facility of Pedestrian Cross Bridge of 17.5 m span and 2.5 m wide. That is why, the writer examines the difference between the two structures in terms of cost. This study comprises planning, detailed engineering design, implementation methods, and cost estimate of castellated steel structures and prestressed concrete voided slab structures.The result of study are as follow : the castellated steel main girder WF 700 x 300 x 13 x 24 at IDR 723,247,800.00 and prestressed concrete voided slab with a size of 970 x 875 diameter 340 mm at IDR 496,282,628.00. From these results, it is concluded that construction of of prestressed concrete voided slab structure is cheaper with price difference IDR 226,965,172.00.Keyword: pedestrian bridge, castellated steel, prestressed concrete voided slab, estimate cost

Design of Concrete Voided Slab of Highway Bridge Pretensioned with CFRP Tendons

The concrete voided slab pretensioned with CFRP tendons is a new type slab for bridge construction. The problems such as the anchorage, loss of prestress, prestressed tendons configuration etc. are discussed, then through the analysis of structure, the characteristics and key points of design methods are put forward. With a 20m span slab as an example, a comparative study is conducted on the concrete voided slab pretensioned with different tendons of CFRP or steel. The analysis shows that the concrete voided slab pretensioned with CFRP tendons is feasible in engineering.

Shear Strength of Void Slab with Polystyrene Forms

Void slab systems with polystyrene form and precast concrete deck have been used to reduce the construction period and the self-weight of the slab. This paper presents experimental works on the shear of the void slabs. Four specimens were tested. The main parameters of experiments were the type of polystyrene forms and the thickness of slab. Shear performances of void slabs were evaluated on the basis of failure patterns, load-displacement curves, and ultimate shear strengths. Based on the test results, the unidirectional void slabs had the best shear resistance performance when they used PF2 type of polystyrene forms. For all specimens that failed due to shear, ultimate shear strength was 52% or higher than nominal shear strength by ACI318-08. This indicates that void slabs have a sufficient shear performance in the truss bar arrangement direction

포스트텐션 중공슬래브의 동적 특성

바닥슬래브의 처짐과 차음 성능을 개선하기 위하여 포스트텐션 중공슬래브가 최근에 자주 사용되고 있다. 동일한 8m 스팬 1층구조물을, 한 구조물은 일반슬래브(solid slab)로, 다른 구조물은 중공슬래브(void slab)로 2개를 제작하여 각 구조물의 바닥슬래브에 포스트텐션을 도입하였다. 중공슬래브의 고유진동수와 감쇠율의 진동특성을 일반슬래브와 비교하였으며, 포스트텐션 도입 후에 일반슬래브와 중공슬래브 각각에 있어서 고유진동수와 감쇠율의 진동특성을 상호 비교하였다. 210mm의 일반슬래브 보다는 250mm 중공슬래브의 1차 고유진동수가 큰 것을 알 수 있다. 포스트텐션 도입 후에도 중공슬래브의 1차 고유진동수는 일반슬래브 보다 큰 것을 알 수 있다. 일반슬래브와 보이드슬래브의 감쇠율은 포스트텐션 도입 전과 도입 후에 거의 동일한 값을 보이는 것을 확인하였다. Post-tensioned void slab is frequently used for improving the deflection and sound proofing. Two one story 8m spanned structures were built. One structure applied post-tensioned solid slab, but the other did post-tensioned void slab. Dynamic characteristics, which is natural frequency and damping ratio, was compared between that of solid slab and void slab before and after post tension. The natural frequency of void slab was greater than that of solid slab before and after post tension. It was shown that damping ratio of solid slab and void slab was almost same at two stages.

Longitudinal anti-cracking analysis for post-tensioned voided slab bridges

Post-tensioned concrete voided slab girders are widely used in highway bridge constructions. To obtain greater section hollow rate and reduce the self-weight, the plate thickness of slab girders are designed to be small with the adoption of flat anchorage system. Since large prestress is applied to the anchor end section, it was found that longitudinal shear cracks are easy to occur along the voided slab girder. The reason is the existence of great shearing effect at the junction area between web and bottom (top) plate in the anchor end section. This paper focuses on the longitudinal anti-cracking problem at the anchor end of post-tensioned concrete voided slab girders. Two possible models for longitudinal anticracking analysis are proposed. Differential element analysis method is adopted to derive the solving formula of the critical cracking state, and then the practical analysis method for longitudinal anti-cracking is established. The influence of some factors on the longitudinal anti-cracking ability is studied. Results show that the section dimensions (thickness of bottom, web and top plate) and prestress eccentricity on web plate are the main factors that influence the anti-cracking ability. Moreover, the proposed method is applied into three engineering examples to make longitudinal anti-cracking verification for the girders. According to the verification results, the design improvements for these girders are determined.

Behaviors of Void Slab with GFRP Reinforcement

Use of hollow material in slab can reduce self-weight and deflection than solid slab with GFRP reinforcement. In this study, bending tests were carried out to evaluate the bending performance of void slabs with GFRP reinforcements. Test results showed that bearing capacity at the compression zone seriously affected the ultimate bending strength of void flexural members. For a design of the void flexural members with GFRP bars, it needs to use the higher concrete strength and to arrange the void foams considering of the crushing failure and distribution of strains and stresses.

The Study on Light Floor Impact Sound Improvement by Void Slab Applied with Surface Covering Materials

The living quality of the Taiwanese citizens keeps rising; the improvement of floor impact sound has being carried out into practical project gradually. The void slab, used to be used in huge span building, is very common in housing building. From reference, the void slab represents the one of the latest architectural facilities, which focuses on the noise improvement for the living quality, by its characteristics of rigidity and lightweight. In order to select an appropriate floor covering material, the experimental investigation based on the standard ISO 140-7 and 140-8 should be carried out to experiment the performance of the bare void slab and the covering materials over the slab for discussing the possibility of material application on the void slab. Therefore, in this study, the noise insulating performance of the void slab through the field experiments in the practical condominium-type housing projects will be tested, and the floor impact sound performance of the selected sample of covering materials (teak wood and carpet) applied on the existing void slab will also be shown in this paper. The results show that the void slab presents good effective performance for heavy floor impact sound, but the void slab should be applied with covering materials to demonstrate efficient improvement toward the light floor impact sound, and the performance varies from materials. The researchers expect that the database could provide designers and constructors the reference of the floor covering materials related to the floor impact sound insulation and reduce the time and the costs issue.

Numerical Simulating Method of the Deflection of Cellular Voided Slabs Fixed Supported by Four Edges

Based on the construct detail, structural behavior of cellular voided slab was analyzed. Differential equilibrium equations and formulae of flexural and torsional stiffness of the cellular voided slabs were given. Solution of deflection of cellular voided slabs fixed supported by four edges were presented by numerical simulating method. Analysis and comparison by elastic finite element method on three group ensamples were carried out. The errors in numerical solutions to finite element method analysis results are little; the solution of deflection was applicable to solve cellular voided slabs fixed supported by four edges.

중공 전이 슬래브의 뚫림 전단 강도

전이슬래브 시스템은 상부 전단벽 구조로부터 하부 기둥으로 하중을 전달하는 구조시스템이다. 이 시스템은 상당한 두께의 슬래브를 필요로 하므로 비경제적이며, 이 단점은 슬래브내에 중공부를 두어 해결할 수 있다. 그리고 이 시스템은 플랫플레이트 구조로써 기둥-슬래브 접합부 부근의 뚫림전단파괴을 일으키는 취성파괴의 위험이 존재한다. 따라서 중공부를 갖는 전이슬래브 시스템의 뚫림전단 성능은 매우 중요하다. 그러나 현행 기준에서는 중공부를 갖는 슬래브의 뚫림전단성능에 대한 명확한 강도산정 규정이 제시되어 있지 않다. 이 연구에서는 중공 시스템의 뚫림전단강도를 알아보기 위하여 실험적 연구를 수행하였으며, 현행기준 및 기존연구를 토대로 실험체의 전단강도를 예측하였다. 그 결과, 중공시스템의 뚫림전단강도는 기둥면으로부터 위험단면 d/2의 위치와 중공부 중심에서의 위험단면으로 계산된 값중 작은 값으로 결정되었다. 여기서 강도 계산을 위하여 위험단면의 유효단면적을 사용하여 계산하였다.

G0601-8-3 ボイドスラブの耐火試験シミュレーション(熱工学(8)燃焼(3))

G0601-8-3 ボイドスラブの耐火試験シミュレーション(熱工学(8)燃焼(3))

数値計算法によるボイドスラブの重量床衝撃音解析(環境工学)

In a previous paper, it was shown through the eigenvalue analysis that the finite element method with coupling of the in-plane and bending displacements (called CIB-FEM) is useful for the calculation of floor impact sounds of void slabs. In a present paper, the heavy weight floor impact sound is directly calculated by the dynamical analysis of void slabs based on CIB-FEM and the characteristic function method for the sound space analysis. As the results of this study the followings are revealed. The results of analysis on the void slab agree well with the measured values. The change in the acoustic radiation efficiency considerably affects a level of the floor impact sound of void slab. The floor impact sound of the void slab is approximately determined by the weight of void. A conversion formula of void slab into the equivalent slab thickness and unit weight gives the accurate results on the calculation of the floor impact sound.

カプセル型中空材を用いた中空スラブ工法の開発 : 構造実験及び設計手法(構造)

This is a technical report for the structural properties of capsule-shaped void slab, which has been developed and introduced to actual buildings in order to eliminate beams at slab ceiling. This void slab has two characteristics. One is high void ratio to provide one of the lightest void slab in Japan. Two is its isotropy nature which enables to design variously outlined slab. Both are verified by the isotopic round shape voids around which concrete is easily cast against their narrow gaps contributing its high void ratio.

位相最適化手法を用いたCFRPによる中空スラブの最適補強

Since the possibility of Tokai or Nankai earthquakes, the reinforcement of the buildings is very important. The method using the CFRP tape is effective for the reinforcement of the floor slab. However, since it is relatively expensive, it is necessary to efficiently affix for the CFRP tape. Therefore, in this paper, the topology optimization method (density approach) is used in order to obtain the optimum layout of the CFRP tape. For this purpose, the FEM program for analyzing the laminate plate is developed, and the density approach with CONLIN optimizer is applied. In this program, the solid element based on the hybrid method is used instead of the conventional plate element. In this study, the void slab is used for the floor structure. The effectiveness of the proposed method is shown by the numerical examples and the comparison with the experiment.

円孔ボイドスラブの曲げ剛性および応力集中評価

Investigation on circular hole Void slab is executed to reduce the slab weight, in which cylindrical steel pipes or other materials are embedded in the center part of cross section in one direction. In this paper, the characteristics of the bending rigidity of the void slab and stress concentrations are confirmed and clarified by direct numerical method. The coefficients of bending rigidity in both directions and of stress concentrations are obtained in accordance with void diameter-thickness ratio. The purpose of this paper is in obtaining the basic design data. This numerical analysis is within the linear theory, and the yield or the limit strength and the final deformation states not evaluated.

ボイドスラブの振動特性に関する研究 : 実構造物における間仕切壁の振動特性への影響

ボイドスラブの振動特性に関する研究 : 実構造物における間仕切壁の振動特性への影響

低張力構成モデルを用いたボイドスラブの非線形解析

低張力構成モデルを用いたボイドスラブの非線形解析

バリアフリー対応型二方向ボイドスラブ

バリアフリー対応型二方向ボイドスラブ

F-46 中空スラブ利用躯体蓄熱空調システムの性能評価 : (その1)躯体蓄熱と24時間空調の比較およびスラブ長さの影響

F-46 中空スラブ利用躯体蓄熱空調システムの性能評価 : (その1)躯体蓄熱と24時間空調の比較およびスラブ長さの影響

ボイドスラブを空調用ダクトとして利用する場合の熱性能の数値解析

Unsteady state thermal behavior of void slabs used as an air-conditioning duct was numerically analyzed with FEM computer program. Non-insulated void slab and eight types of insulated void slab were simulated. The following results were obtained: (1) When a void slab is used as a floor, inside surface of the void should be insulated. If the thickness of insulation exceeds 30 mm, the temperature difference on the floor surface becomes less than 1 degree C and the surface condensation during cooling period can almost be avoided. (2) When a void slab is used as a roof, inside surface of the void as well as exterior surface of the roof should be insulated. Thc recommended thickness of insulation is more than 30mm for inside surface of the void and 100 mm for exterior surface of thc roof, respectively.

Prediction of crack widths in circular-voided reintorced concrete slabs subjected transverse to bending

Synopsis When concrete slabs containing longitudinal circular voids are subjected to transverse bending, a complex stress pattern occurs and the first cracks appear at the inverts of the voids. If sufficient reinforcement is provided in the tension flange, subsequent outer-face cracks appear at about a quarter of the void diameter each side of the first cracks. Previous studies of the cracking behaviour of transverse strips of voided slabs have shown that, due to the predetermined and highly-concentrated type of cracking, very wide and uncontrollable cracks sometimes occur. Since the equations which are currently used for predicting crack widths in solid slabs do not take into consideration the effect of the presence of voids on the crack formation process, a new method is needed for predicting the widths of cracks in voided slabs subjected to transverse bending. This paper presents a suitable method which gives reasonable predictions of the widths of such cracks. The method was evolved from both theoretical and experimental investigations involving tests on fourteen 1: 3·33 scale model transverse strips of practical voided slabs. Consideration is also given to the amounts of reinforcement which are needed (a) to prevent premature yielding of the steel, (b) to achieve a controlled crack pattern, and (c) to limit the widths of the cracks to acceptable levels as specified in BS 5400, the British Standard Code of Practice for concrete bridges.