Multivariable Regression Strength Model for Steel Fiber-Reinforced Concrete Beams under Torsion

Torsional behavior and an analysis of steel fiber reinforced concrete (SFRC) beams are investigated in this paper. The purpose of this study is twofold: to examine the torsion strength models for SFRC beams available in the literature and to address properly verified design formulations for SFRC beams under torsion. A total of 210 SFRC beams tested under torsion from 16 different experimental investigations around the world are compiled. The few strength models available from the literature are adapted herein and are used to calculate the torsional strength of the beams. The predicted strength is compared with the experimental values measured by the performed torsional tests and these comparisons showed room for improvement. First, a proposed model is based on optimizing the constants of the existing formulations using multi-linear regression. Furthermore, a second model is proposed, which is based on modifying the American Concrete Institute (ACI) design code for reinforced concrete (RC) members to include the effect of steel fibers on the torsional capacity of SFRC beams. Applications of the proposed models showed better compliance and consistency with the experimental results compared to the available design models, providing safe and verified predictions. Furthermore, the second model implements the ACI code for RC using a simple and easy-to-apply formulation.

Algorithm of Strength Calculation of Drive Elements of a Roller Conveyor

The paper shows an algorithm for determining the load on the electric motor of run-out conveyor starting from determination of the first moment of no load operation during slab conveying, slipping torque of the rollers along the surface of the conveyed billet and ending with the choice of the electric motor. It also covers an algorithm for strength calculations of the run-out conveyor roller, which includes the calculation of the moments and forces acting on the conveyor roller and its supports, the calculation of static strength and torsion strength, calculation of roller deflection of the conveyor rollers as well as the selection and verification calculation of conveyor roller bearings.

Studi Komparasi Pembebanan Analisis Jembatan Cibaruyan dengan Pembebanan Jembatan Berdasarkan RSNI T-02-2005 dan SNI 1725:2016. (Hal. 75-86)

ABSTRAK Jembatan beton prategang merupakan jenis jembatan yang banyak digunakan di Indonesia karena memiliki kekuatan yang tinggi dan berat jembatan lebih ringan. Jembatan Cibaruyan yang dibangun pada tahun 2014 dan berada di Kabupaten Ciamis menggunakan jenis jembatan beton prategang tipe I girder, mengacu pada peraturan RSNI T-02-2005. Seiring dengan perubahan waktu telah ada standar pembebanan jembatan terbaru yaitu SNI 1725:2016. Karena adanya perubahan tersebut, maka akan dilakukan studi komparasi antara kedua peraturan. Pemodelan jembatan menggunakan program SAP2000 dengan menganalisis kombinasi pembebanan, perhitungan gaya prategang, tegangan girder yang terjadi, lendutan, kekuatan momen lentur, gaya torsi, dan kekuatan geser penampang girder. Dari hasil analisis didapatkan bahwa hasil pembebanan struktur atas Jembatan Cibaruyan dengan SNI 1725:2016 memiliki perbedaan momen lentur lebih besar 0,975% dibandingkan RSNI T-02-2005, gaya prategang pada RSNI T-02-2005 lebih besar 1,951% dibanding SNI 1725:2016, gaya geser dan torsi pada SNI 1725:2016 lebih besar 5,615% dan 26,127% dibandingkan RSNI T-02-2005. Kata kunci: jembatan prategang, RSNI T-02-2005, SNI 1725:2016 ABSTRACT The prestressed concrete bridge is a type of bridge that is widely used in Indonesia because it has high strength with a light structural weight. The Cibaruyan bridge in Ciamis city uses type I girder prestressed concrete bridge built in 2014 referring to the regulation of RSNI T-02-2005. As time goes by there has been a change in the regulations. SAP 2000 was used to model the bridge with the results of the analysis obtained in the form of a combination of loading, calculation of prestressing forces, stresses that occur, deflection, flexural strength, torsion strength, and shear strength. From the results of the analysis it was found that the structure of the Cibaruyan Bridge with SNI 1725:2016 had a greater bending strength of 0,975% compared to RSNI T-02-2005, the prestressed force on RSNI T-02-2005 was 1.951% greater than SNI 1725: 2016, shear force and torsion force at SNI 1725:2016 greater 5.615% and 26.127% compared to RSNI T-02-2005. Keywords: prestressed bridge, RSNI T-02-2005, SNI 1725:2016

ANALISIS KAPASITAS PUNTIR ELEMEN BALOK BETON MUTU TINGGI DENGAN SUBSTITUSI ADITIF, AGREGAT HALUS SERTA AGREGAT KASAR (PENGGUNAAN FLY ASH BATU BARA, PASIR POZZOLAN DAN CANGKANG SAWIT)

Along with the construction development which is not symmetrical and both the column and the beam made small then the torsion load highly affect the building structure. The torsion load often occurs in the building components such as beam, column and the joint of column and beam. The loads of floor plates and small beam will create a torsion moment on the certain beam. Earthquake can cause dangerous torsion force in all elements of building constructions. Like the load outside the center of the mass in which the torsion stress can be very high. This research aims to find out the torsion capacity on hybrid high performance concrete beam element in which the hybrid high performance concrete using additive alternative materials, by using 7 test objects variations, the size of the test objects used is 20 x 25 x 120 cm3 and the test done for 28 days of concrete period. From the test output obtained that the highest torsion moment found out in Test object number 6 (BU6) using pozzolanic fly Ash (10%) + fine aggregate of the sand pozzolan (10%) + coarse aggregate of palm kernel shell (40%) + Nano material filler of iron ore as 10.4 kNm. The highest torsion angle is also created on BU6 as 0,0246 rad. The concrete performance highly affects the torsion strength, the highest concrete performance is found out from BU6 which is 59,48 MPa.

Torsion Strength Measurement of Engineering Ceramics

This paper discusses the relationship between torsion strength and bending strength of Al2O3 and Si3N4 ceramics. Measurement of the torsion strength was carried out by a simplified torsion test method proposed by Yasuda and Tsutsumi. In this experiment, the average torsion strength was approximately 2/3 of its average bending strength for both ceramics. By estimating the characteristic strength σ0 in Weibull distribution from the strength data, σ0 in torsion is almost the same as that in bending, which agrees to the basic discussion in mechanics of materials. The characteristic strength σ0 is one of the normalized strength by eliminating the effects of specimen shape, dimensions and also its stress distribution, and therefore the apparent difference between torsion and bending strengths can be explained by the difference in effective surface area (Conversely, the measured torsion strength data by the simplified method must be reasonable). It reveals that biaxial fracture in tension/compression during torsion test is equivalent to uniaxial tensile fracture by this experiment.