PERILAKU RANGKAK SUSUT TERHADAP LENDUTAN STRUKTUR JEMBATAN BENTANG PANJANG

Jembatan Lemah Ireng 1 pada ruas jalan Tol Semarang-Bawen terbuat dari beton prategang dengan panjang total 879 m. Pada masa konstruksi dua perbedaan kondisi teknik terhadap rencana, yakni perubahan material pasir dan perubahan perpindahan traveler. Keduanya diduga sebagai penyebab perbedaan elevasi desain dengan elevasi aktual sehingga dilakukan levelling aspal dengan tebal bervariasi. Jembatan ini didesain untuk memenuhi masa layan 100 tahun namun berdasarkan kondisi aktual, diperlukan peninjauan terhadap perilaku dan kuat layan jembatan hingga umur rencana. Dengan pengaruh variasi pembebanan jangka panjang (rangkak susut) dan kondisi perubahan teknis akibat penambahan aspal, penelitian rangkak susut ini perlu dilakukan untuk mengetahui perilaku lendutan pada gelagar boks jembatan hingga umur rencana. Beberapa tahapan pembebanan yang dilakukan adalah menerapkan beban levelling aspal, dan beban rangkak dan susut dengan menggunakan variasi durasi jangka panjang dengan interval 5, 10 , 15, 20, 40, 60, 80 dan 100 tahun. Analisis dilakukan secara linear statik serta memanfaatkan fasilitas Construction Stage Analysis untuk efek time-dependent pada software Midas Civil 2011. Penelitian ini dilakukan dengan hanya meninjau aksi tetap. Perilaku rangkak susut jembatan cukup signifikan di 5 tahun pertama setelah konstruksi selesai. Lendutan maksimum rangkak susut dan total berada di bentang terpanjang (P4-P5)  masing-masing sebesar 17,53 dan 25,71 cm. Lendutan yang terjadi hingga umur rencana 100 tahun masih dalam batas izin, namun tetap perlu pengawasan yang terencana. Dampak minimum rangkak susut terhadap total lendutan pada jembatan Lemah Ireng 1 sebesar 45%. Hal ini menunjukkan rangkak susut terhadap defleksi total hingga umur rencana merupakan efek jangka panjang yang relatif besar

Perbaikan Balok Beton Bertulang dengan Metode Jacketing dengan Bahan Ferosemen Akibat Beban Siklik pada Beban Ultimit

A large number of buildings construction was made of reinforced concrete structure, composed of concrete and steel. The reinforced concrete structure elements could experience damage due to earthquake, from light to heavy failure, such as heavy bending-shear crack near the beam column joint. It is necessary, therefore, to repair the structure adopted good method and workability. The specimens were part of exterior beam-column joint model. Cyclic lateral load was applied to simulate earthquake load. This research used 3 specimens: US-1, the shear damage specimen as the result of first-step loaded test, then are repaired by using 1 layer rectangular galvanized welded wire mesh became R-US.1. US-2, the shear damage specimen as the result of first-step loaded test, then are repaired by using 2 layers rectangular galvanized welded wire mesh became R-US.2. UBB, the bending damage specimen as the result of first-step loaded test, then are repaired by using 2 layers rectangular galvanized welded wire mesh became R-UBB.   The result showed that the retrofitted on ultimate load by using jacketing ferrocement increased the ultimate strength capacity of 91,667%(US-1 to R-US.1), 81,818%(US-2 to R.US.2) and 28,571%(UBB to R-UBB) respectively. Increasing the hysteretic energy were 215, 66%(US-1 to R-US.1), 273,11%(US-2 to R.US-2) and 389, 84%(UBB to R-UBB). The ductility of retrofitted specimen 6,64(R-US.1) and 12,72(R-US.2). The initial stiffness of retrofitted specimens decreased 60%(US-1 to R-US.1), 40%(US-2 to R-US.2) and 18%(UBB to R-UBB)

The Estimation Modeling of Abutment Volume with Variations of Bridge Span, Abutment Height, and Seismic Zone

The initial cost of a bridge project determined using an estimation model depends on the dimensions, types, and materials but only a few studies have included bridge location as a determinant variable. The inclusion of the location is, however, important due to the different seismic accelerations and seismic load analysis attached to it. Therefore, this study aimed to create a model to calculate the quantity of materials needed for the construction of abutment in different locations with a PCI-Girder superstructure. Moreover, the data used for the quantity estimation model was derived from the abutment design results and those associated with concrete and reinforcing steel quantities were based on the variations of the bridge span at 20 m, 25 m, 30 m, 35 m, and 40 m, abutment height at 4 m, 6 m, and 8 m, and seismic zone 1, 2, 3, and 4. Meanwhile, the volume estimation models were obtained through multiple linear regression analysis. The results showed a very strong correlation between the span of the bridge and the height of abutment with the dependent variables while the seismic zone was observed to have a strong correlation with the dependent variables but was unable to meet the linear regression assumptions. Therefore, the statistical analysis was conducted separately for each seismic zone and the data for abutment height was transformed from H into H2. This study developed 8 models with R2 values ranging between 0.983 – 0.997 and this means they were adequately designed to estimate abutment volumes with a PCI-Girder superstructure

Bending capacity of reinforced concrete beam with a rough aggregate of 2/3 teak pieces

The development of science, especially in civil engineering, demands a better concrete technology. Replacing the rough aggregate with teak pieces of length 2 cm, width 3 cm, and height 2 cm was tried to reduce the weight of the concrete. This wood was selected because of its light. The testing phases included: testing of concrete cylinders and testing of reinforced concrete beam bending. The bending beam test was done by making a specimen with dimension of beam: width 120 mm, height 150 mm, and length 1200 mm. The main reinforcements used were 2Ø10 mm and 3Ø10. For the chock, Ø6-50 reinforcement bar was used. On the test of concrete cylinder results with soaked rough aggregates, it was found that compressive strength at 28 days old was 5.09 MPa and 4.74 MPa for non-soaked aggregate. On the test of reinforced concrete beams with 2 pieces of tensile reinforcement, it was found the average maximum load of 26300 N and average deflection of 6.99 mm. The average of reinforced concrete beam with 3 pieces of tensile reinforcement was 30500 N and average deflection of 8.66 mm. The bending strength of reinforced beam with 3 pieces of tensile reinforcement average was 5.34.106 Nmm. The comparison of calculation result between experiment and theory was found that load and moment for 2 pieces of tensile reinforcement was 0,72%, while comparison between load and moment for 3 pieces of tensile reinforcement was 0,58%. Keywords: teak wood, lightweight concrete, load beam capacity

PENGARUH PENAMBAHAN FIBER LOKAL PADA PERILAKU TORSI KOLOM BETON BERTULANG PENAMPANG LINGKARAN DENGAN TULANGAN SPIRAL (THE EFFECT OF LOCAL FIBER ON THE TORSIONAL OF SPIRALLY CIRCULAR REINFORCED CONCRETE COLUMNS)

ABSTRACT Columns are structural element, which are dominantly axially loaded. However sometimes columns are laterally loaded by shear, bending, and torsion. In order to make column have high ductility, can be added by fiber material. The aim of the research is to find the effect of local fiber on the behavior of circular torsion concrete column with spirally reinforcement. This research is held on 6 (six) columns, three of them are normal concrete columns and the others are fiber concrete columns. The circular columns have 200 mm diameter and 950 mm length. The columns are fixed on rigid floor. The ratio of longitudinal reinforcement each column is 2,08 % and ratio of spiral reinforcement 1,45 %. The local fiber is one percent, with aspect ratio (lid) 60. Every column is loaded under constant effectiv axial load 210,186 kN and cyclic torsion until failure. The result of the research shows that with 1 % local fiber the tension strength (splitting) of the fiber concrete increase up to 40,83 %, and the compression strength is almost the same as normal concrete. The strnght of spirally reinforcement are 201,62 Mpa and 163,19 rispec- tively on normal and fiber concrete. The local fiber does not influence on first crack torsion, but increas on ultimit strength of the concrete columns, and ductility of the columns by first crack is increassed 125 %, more than normal concrete columns. The first crack of normal concrete columns experiment are higher then Skew Bending and Space Truss method, 49,81 % and 15,17 % repectively. The first crack of fiberconcrete columns experiment eqaul Skew Bending method, but lower then Space Truss 25,85 %. The ultimate torsion experiment of normal concrete columns are higher then Skew Bending and Space Truss method, 20,57 % and 28,25 % respetively. Tthe ultimate torsion fiber concrete columnsexperiment are higher than Skew Bending 12,02 %, but lower then Space Truss 13,56 %. Before the first crack, the increased angle torsion linear to torsion, and so to be large and collapse. The normal concrete columns spall suddenly, but the fiber concrete columns are not. The spalling area of normal concrete column is larger than fiber concrete column. The stiffnes of fiber concrete column is higher then normal concrete column 7,3 %. Keywords : circular column, spirally reinforcement, torsion, cyclic, fiber concrete, spallin

Retrofitting on Flexural Strength of RC Columns Using Polyester Resin Concrete

Concrete column structures damages due to flexural moment need to be repaired and strengthened to avoid of sudden failure by applying appropriate methods. The method applied in this study was retrofitting by applying polyester resin concrete. In order to know the effect of polyester resin concrete against axial load capacity, stiffness, ductility and the damage pattern of columns by eccentrically loaded, an experimental laboratory was carried out. In this study, three column specimens are tested. The dimension of the specimen is 150 mm x 150 mm and the high of the column are 1200 mm with the effective high is 600 mm and 600 mm for corbel. The column specimens have a fixed eccentricity of 50 mm. First, initial column tested before yield point of reinforcing bar reached and concrete crack limited to 0,4mm. Further, retrofitting applied to each initial column specimen using normal concrete and polyester resin concrete with the level of resin 15% and 20%, respectively. Retrofitting column tested again with the same loading of initial column until it reaches the collapse load. The result of experiment compares to analysis method by Nawy and Whitney which represent the analysis of normal concrete column capacity. The result showed that levels of resin to be used is 20% because of better workability compared to 15% resin. Further, compressive test on resin concrete cylinder showed that the resin level at 15% and 20% are 82.82 MPa and 76.65 MPa, respectively. The strength of KR-ii decreased about 33.523%. The strength of KR-15ii and KR-20ii increased 5.08% and 24.827% respectively compared to initial column. Specimen column stiffness KR-ii. KR-15ii and KR-20ii decreased about 76.22%, 24.50% and 37.65%, respectively from the initial column. Furthermore, ductility of KR-ii, KR-15ii and KR-20ii decreased about 1.512, 1.250 and 2.50, respectively. The changes of the ultimate capacity load of KR-ii, KR-15ii and KR-20ii by Nawy Method respectively -26.54%, 12.66%, and 13.83%, whereas the method of Whitney respectively -17.68%, 26.25%, and 27.56%. The use of polyester resin concrete can change the pattern of collapse from brittle to ductile columns.Keywords: retrofit, ductility, stiffness, flexural column, eccentricit

Analisis Pengaruh Jenis Dan Tebal Spray Applied Materials Fireproofing Terhadap Ketahanan Api Balok Baja

Protection against fire is important to maintain the strength of the structure. Fireproofing can be used as an anticipation to reduce the spread of the fire. Evaluation the effect of fire on structural elements is generally performed by a numerical approach. Analysis of simple beam IWF 150x75x5x7 with 3,5 span length using varied fireproofing such as CAFCO 300, Carboline Type 5 MD and Typo WR-AFD was conducted with Abaqus CAE 6.11-1. Nonlinear material properties of steel based on Eurocode 3 while thermal properties of fireproofing are constant. Thickness variation of fireproofing are 10 and 20 mm. Pressure load was carried on the top flange of steel beam. ASTM E-119 used as a thermal load by conduction on 3 sides (left, right and bottom) with duration of 2 hours. The results showed that type and thickness variation of the fireproofing has a significant effect on the fire resistance of steel beams. The highest temperatures occur when steel coated by Typo WR-AFP and the lower temperatures occur when steel coated by CAFCO 300. Maximum deflection of steel beam occurred when steel coated by Typo WR-AFD. Steel beam with Typo WR-AFD experiencing a critical deflection with the fastest time of 4.80 minutes at 10 mm thick and 9.10 min at 20 mm thick. Steel beam with 10 mm thick of fireproofing achieve yield stress when the time 14.03, 8.86 and 5, 12 minutes for fireproofing CAFCO 300, Carboline Type 5 MD and Typo-AFD WR. Steel beam with 20 mm thick of fireproofing experiencing yield stress only on Typo WR-AFD at 10.22 minutes

Perkuatan Lentur Pelat Lantai Tampang Persegi dengan Penambahan Tulangan Tarik dan Komposit Mortar

Overloading of structures can cause failure. In order to continue using them, strengthening is required. In this research elastic strengthening was carried out on concrete floor plates by means of tensile reinforcement addition, and mortar composite additionto apply epoxy resin. Four reinforced concrete slabs, consisted of one control slab (PK), one monolith slab (PM), one strengthened slab (PPE) and one unstrengthened slab (PPTE). Specimen dimensions were 700 mm x 1500 mm x 60 mm for the PK, and 700 mm x 1500 mm x 100 mm for the others. Specimens were placed on a simply supported loading frame, and statically loaded at their mid-span. Numerical analysis using Response-2000 software package was carried out for comparison with the experiment al result. It was found out that the flexural capacity of the PK, PPE, PPTE and PM specimens are 5,99 kNm, 12,52 kNm, 13,87 kNm and 21,38 kNm, respectively. In comparison with that of thePK, flexural capacity of the PPE and PPTE specimens was found to increase by 109,019 % and 131,55 %, respectively. The increase of stiffness was 324,77 % and 430,21 % for the PPE and PPTE specimens, respectively. The ductility factor of the PPE and PPTE increase 29,63 % and 19,03 %, respectively . The PK and PM specimen s experienced flexural failure, while the PPE and PPTE specimens experienced debondingfailure

NUMERICAL MODELING OF APPLIED NEAR-SURFACE MOUNTED ON REINFORCEMENT SLAB WITH ABAQUS CAE

Reinforced concrete (RC) is the most applied material in modern construction. Research on strengthening RC concrete members has also been widely carried out. Over time, concrete elements might deteriorate due to several factors, such as load, creep, or any other environmental aspects, leading to stiffness or strength reduction. Following the rapid development of studies on RC, the development of strengthening of concrete structure Reinforced Polymer (FRP) is also the case to overcome concrete deterioration. To improve the strength capacity of the concrete beams, Ega (2020) investigated the effect of epoxy adhesive length on the bonding strength of rebar using several laboratory tests. The result of the study yielded that the optimum length for the epoxy was 150 mm with a strength increase of up to 165.3%. The laboratory tests were modeled numerically using Abaqus CAE to simulate the behavior of the RC beam. Investigating the ideal mesh size and crack model behavior was the first stage of modeling. An RC beam previously experimentally tested by Ega (2020) was used for validation. Therefore, this research compares the numerical results from the Abaqus simulation with experimental data results. The specimen tested for this research was a concrete beam of 1200 mm x 450 mm x 120 mm subjected to 3-point loading. This study aims to develop a suitable numerical model for one of the tested beams and facilitate the design of NSM that follows the character of the previous research