Pengaruh Penempatan Penyambungan Pada Perilaku Rangkaian Balok-kolom Beton Pracetak Bagian Sisi Luar

Influence of Connection Placement to the Behavior of Precast Concrete Exterior Beam-Column Joint. This paperpresents an experimental study on the influence of connection placement to the behaviour of exterior beamcolumnjoint of precast concrete structure under semi cyclic loading. Four half-scale beam-column specimens wereinvestigated. Three beam-columns were jointed through connection that are placed in beam-column joint region and theforth is connected at the plastic hinge potensial region of the beam. Crack patterns, strength, stiffness and ductility ofthe test specimens have been evaluated. The test result indicated that all beam-column specimens show good ductilitybehavior

Long-term Shrinkage Empirical Model of High Performance Concrete in Humid Tropical Weather

This paper represents a long-term shrinkage empirical model of high performance concrete (HPC) with and without fly ash based on experimental research in which compressive strength was 60MPa. Specimens measuring 150x150x600 mm3 were used. Observations were conducted over the two year periode using an  embeded vibrating wire strain gauge. As a result, the empirical model was  in agreement with experimental results.  Addicionally comparisons were made with ACI 209R, AS 3600-2009 and Eurocode 2. The results showed that ACI 209R was about 60% and 75% of HPC with and without fly ash respectively.  Eurocode 2 was underestimated for both HPC (58%) and HPC without fly ash (73%). AS 3600-2009 was 16% higher than HPC with fly ash but this condition is suspectable to change during longer observation periode because AS 3600-2900 has a lower slope than the empirical model, while HPC without fly ash was overestimated (93%).  Model representation shows  significant differences in form compared to ACI 209R; and AS 3600, and similarity in form compared to Eurocode 2. Keywords: Shrinkage, High performance concrete, Empirical model, Humid tropical weathe

PENGARUH PENEMPATAN PENYAMBUNGAN PADA PERILAKU RANGKAIAN BALOK-KOLOM BETON PRACETAK BAGIAN SISI LUAR

Influence of Connection Placement to the Behavior of Precast Concrete Exterior Beam-Column Joint. This paperpresents an experimental study on the influence of connection placement to the behaviour of exterior beamcolumnjoint of precast concrete structure under semi cyclic loading. Four half-scale beam-column specimens wereinvestigated. Three beam-columns were jointed through connection that are placed in beam-column joint region and theforth is connected at the plastic hinge potensial region of the beam. Crack patterns, strength, stiffness and ductility ofthe test specimens have been evaluated. The test result indicated that all beam-column specimens show good ductilitybehavior.Keywords: precast concrete, beam-column joint, reinforced concret

The Effect of Superplasticizer Type on Compression Failure of High–Strength Concrete

Although superplasticizer has been used widely on buildings and bridge structures around the world, the concrete’s behavior has not yet been understood well by civil engineers.  The use of superplasticizer should guarantee that abnormal failure does not occur. This paper presents  different compression failure types of cylindrical specimens using two kinds of superplasticizer based on experimental research for compression test of high strength concrete  (HSC) with a minimum compressive strength of 60 MPa. Cylindrical specimens measuring 15 cm in diameter and 30 cm of high were used. Seven mixtures using H superplasticizer and 7 mixtures using V superplasticizer were used. Failure observations were conducted as compression load was applied until failure occured. There were two types of compression failure which were vertical and horizontal according to two types of FT-IR graphs of superplasticizer. FT-IR simple fingerprint of superplasticizer exhibited normal compressive failure, while complex fingerprint showed dangerous compressive failure. Keywords: Superplasticizer, Compression failure, High-strength concrete, Fingerprin

Rheological Model of Concrete Shrinkage

This paper discusses the shrinkage rheological model of high-performance concrete with a compressive strength of 60 MPa. This is based on experimental research in Indonesia. Three specimens measuring 150 mm × 150 mm × 600 mm were used. Specimens were placed in a conditioned room with a temperature of 28 3oC and relative humidity of 72±5%. Observations were conducted over 7–800 days using an embedded vibrating wire strain gauge for each specimen. As a result, the shrinkage rheological model was single or multi Kelvin-Voigt in series with time-dependent disturber flow in it. Disturber flow depends on product hydration growth, weather, pore number, size, and distribution. The model agrees with experimental results. Moreover, it also fits the results using high strength concrete column and high strength self - compacting concrete cylinder

Long Term Deformation of Beams and Columns of High Performance Concrete

The columns of a building must be stronger than the beams. The aim of this study is to obtain the cause of the long-term deformation difference by shrinkage between the beams and columns of high performance concrete with compressive strength of 60 MPa. This research was done experimentally in Indonesia during 410 days. Specimens measuring 150 mm × 150 mm × 600 mm were used, 3 pieces for the beams and 2 pieces for the columns. Deformation was obtained by using an embedded vibrating wire strain gauge for each specimen. The difference of long-term deformation in columns and beams is in their  autogenous deformation behavior. This is because during the autogenous phase, swelling abnormally occurs in the column before shrinkage occurs. The abnormal swelling is caused by the press of its own weight. This phenomenon does not occur in beams. In the age range of 1 to 200 days, the behavior of the beam deformation has a similar pattern to the deformation behavior of the column with a high deformation rate. After that, at 200–410 days, column deformation changes to a very slow deformation rate. Long-term deformation in columns is lower (64%) than in the beams at 410 days age

PENGARUH MOTIVASI DAN SIKAP PELANGGAN TERHADAP KEPUTUSAN PEMBELIAN ULANG

This research entitled "The Influence of Motivation and Customer Attitudes toward Purchase Decision (Case Study On My Self-service Reny in Surabaya)". This study aims to determine the influence of customer motivation and attitudes toward the re-purchase decision at Reny self-service Surabaya. The population in this study are consumers who shop at Reny Swalayan-ku Surabaya minimum age 18 years and who has made a minimum purchase twice in Reny Swalayan-ku Surabaya and samples taken as many as 100 respondents. Variables used are motivation, customer attitude and purchasing decision.Method of data collection using questionnaire method by using technique of Non Probability Sampling that is accidental sampling. The data obtained were analyzed using multiple linear regression analysis which was processed with the help of SPSS program application.The results obtained conclusion as follows:1. There is an individual influence of motivation to the repurchase decision and the customer's attitude toward the repeat purchase decision is proven and accepted reality of partial test result (t) obtained with significant level <0,05.2. There is mutual influence of customer's motivation and attitudes toward the repeat purchase decision proven and accepted reality of partial test result (F) obtained with significant level <0,000.3. Variable of motivation and attitude of customer have strong relation to repurchase decision equal to 6,44% and besides that independent variable have contribution equal to 65,1% to dependent variable and the rest 34,9% influenced by other variable.Keywords: Motivation, Customer Attitude and Purchase Decisio

Error Estimation for the DKMQ24 Shell Element Using Various Recovery Methods

This paper presents an application of DKMQ24 element for error estimation using error estimator Z2 and various recovery methods such as Averaging (AVR), Projection (PROJ) and Superconvergent Patch Recovery (SPR). The stresses found by using these recovery methods will be compared to the reference solution. We found that Averaging and SPR method gave better results compared with the Projection method

Study on the effect of pre-treatment of Oil Palm Shell (OPS) as coarse aggregate using hot water 50-°C and room temperature water 28-°C to lightweight concrete strength

With a rapidly growing population, the need for homes is increasing, which means the demand for housing material is also increasing in Indonesia. On the other hand, as the largest producer of palm oil in the world, Indonesia produces almost half of the world’s palm oil inventories. Oil palm shells (OPS) are agricultural solid end products from palm oil manufacturing processes. In this research, the use of OPS waste as substitution materials for making concrete is investigated. In order to be used as structural building material, some mechanical properties of materials must achieve the requirements of the National Standard SNI. The general objective of this research is to understand the effect of the pretreatment process on OPS aggregate on the mechanical behaviour of lightweight concrete. To do so, first, pre-treatment on the OPS is performed using hot water (50°C) and room temperature water (26-28°C). Second, by using the most effective mixed proportions from previous research in laboratory, pre-treated OPS is used to cast concrete. Third, some experimental tests are carried out to evaluate its mechanical properties, such as: concrete compressive strength, flexural strength and tensile strength (split test). Then, behaviour from both different treatments are compared and discussed. Finally, this research can determine which method gives better result for the application of OPS as biosource substituent material

Flexural behaviour of reinforced lightweight concrete beam using hot water pre-treated oil palm shell coarse aggregate

Along with the increasing demand for habitation in Indonesia, the need for concrete as the most favourable housing material is escalating. Oil Palm Shell (OPS) as coarse aggregate material is a possible alternatives material in concrete mix proportions. This possible choice of material not only can fulfil the requirements of the materials, but is also capable of reducing the problem of OPS waste in Indonesia. As OPS concrete compressive strength in previous studies in laboratory is in the range of 20-23 MPa, studies on larger elements of structure become interesting. This research presents flexure behaviour of lightweight concrete beams using OPS replacing natural coarse aggregates under four-point loading application. OPS is firstly pre-treated using hot water at 50°C based on previous research. In this study, a series of tests was conducted on two samples of identical beam with dimension of 15×25×300 cm. This size represents the typical dimension of beam used in two-storey houses in Indonesia. Mechanical response due to bending that occurs in OPS lightweight concrete beam is presented. Observation on the beam is emphasised on the pure bending area