Hery Riyanto - Academia.edu (original) (raw)

Papers by Hery Riyanto

To obtain the performance of Recycled Polyester Resin as jointers material for segmental precast ... more To obtain the performance of Recycled Polyester Resin as jointers material for segmental precast concrete beams, several experiments have been done at the Laboratory of Structure and Materials - ITB Bandung. The experiments included: correlation between the composition and its viscosity, setting-time, compressive strength, tensile strength, and structural application on varied surface joint-area and joint-width. The results of those experiments show that in the original composition with viscosity of 920 cps, setting-time of 33 minutes, compressive strength of 121.19 MPa (at three days age), tensile strength of 34.22 MPa, elasticity modulus of 1498 MPa. After added with 30% (by weight of resin) styrene monomer, its has viscosity of 105 cps, setting-time 63 minutes , compressive strength of 96.20 MPa (at three days age), tensile strength of 22.37 MPa and elasticity modulus of 1600 MPa. The third point static loading test on the 3 x (10 mm x 10 mm x 10 mm) segmental simple beam using l...

Civil Engineering and Architecture

The need for environmentally friendly concrete that has above average compressive strength contin... more The need for environmentally friendly concrete that has above average compressive strength continues to be pursued to meet the infrastructure needs of humans. The availability of materials derived from organic waste such as clamshells is thought to be used as an aggregate from concrete which is more environmentally friendly when combined with previously known inorganic materials. The purpose of this study was to optimize the compressive strength of concrete-filled with clamshell powder (CSP), iron sand, and epoxy resin. An optimization approach based on response surface methodology (RSM) was used in this study. Iron sand used is 10% (w/w). The CSP used is in the range of 1 to 4% (w/w). The epoxy resin used is in the range of 10.5 to 14.40% (w/w). The temperature and time of curing were carried out in 301 to 333 K and 4 hours, respectively. The age of concrete is measured in the range of 1 to 28 days. The cylindrical molded concrete has a diameter and height of 100 mm and 200 mm, respectively. All samples were measured for compressive strength using the UTM RTF-1350 (capacity of 250 kN). The concrete composition with epoxy resin (11.93%, w/w) to the standard concrete aggregate mixture produced the highest compressive strength (71.49 MPa). However, the addition of CSP as a filler in concrete has provided a compressive strength (31.18 MPa) above concrete by the Indonesian National Standard (SNI). The combination of CSP and epoxy resin under high-temperature curing conditions is possible to increase the compressive strength of concrete to 45.65 MPa.

Mathematical Modelling of Engineering Problems

The proportions of the concrete are critical for obtaining a high-strength, high-quality product.... more The proportions of the concrete are critical for obtaining a high-strength, high-quality product. Different concrete grades may support varying loads and have varying ratios. Therefore, the objectivity of this research is to study mechanical performance from concrete treated with iron sand, glass powder, and hot water curing. The level of iron sand and glass powder treatment added to the SNI concrete composition is 2% to 10%, 1% to 5%, (w/w), respectively. The curing time and temperature were applied between 1 hr to 4 hr and 301 K to 343 K. The compressive strength of the concrete was tested on 0, 1, 3, 7, and 28 days after molding using UTM with a combination of linear regression and response surface models for optimization. The addition of iron sand and glass powder to increase the best compressive strength was 10%, 2.45%, respectively. Iron sand treatment of 10% combined with glass powder filler 3.04% was predicted to give the best compressive strength of 32.50 MPa. The compressi...

Jurnal Teknik Sipil Bandar Lampung, Oct 31, 2013

Penelitian ini bertujuan untuk mengetahui perilaku statis elemen struktur balok beton bertulang p... more Penelitian ini bertujuan untuk mengetahui perilaku statis elemen struktur balok beton bertulang pracetak yang disambung dengan sambungan basah. Benda uji yang digunakan adalah balok beton bertulang 30 MPa dengan 6 buah tulangan utama diameter 8 mm yang diletakkan di atas dua tumpuan sendi rol pada masing-masing ujungnya mempunyai penampang prismatis segi empat 10x18 cm 2 . Sambungan basah adalah sambungan yang menggunakan bahan beton polimer 40 MPa dengan metoda penyambungan menggunakan metoda prepacked. Kajian perilaku statis pada model benda uji untuk mengetahui kekuatan lentur struktur, kekakuan dan pola retak struktur balok akibat beban statis yang diletakkan di tengah bentang. Beban statis adalah beban mempunyai arah dan besar tetap. Hasil kajian struktur beton yang disambung kemudian dibandingkan dengan struktur yang tanpa sambungan (monolit). Kekuatan balok dengan sambungan basah lebih kecil daripada kekuatan balok monolit.

Universitas Bandar Lampung, Apr 30, 2016

Jurnal Teknik Sipil Bandar Lampung, Apr 30, 2014

Bahan - bahan campuran beton terdiri dari agregat kasar (kerikil), agregat halus (pasir), bahan p... more Bahan - bahan campuran beton terdiri dari agregat kasar (kerikil), agregat halus (pasir), bahan perekat (semen) dan air secukupnya. Beton mempunyai kekuatan tekan yang cukup besar, namun sangat lemah terhadap kuat tarik. Karena itu penggunaan beton selalu dipadukan dengan bahan yang mempunyai kuat tarik tinggi yaitu baja. Nilai kuat tekan beton relatif tinggi dibandingkan dengan kuat tariknya, dan beton merupakan bahan yang bersifat getas. Nilai kuat tariknya hanya berkisar 9%-15% saja dari kuat tekannya. Beton dengan tulangan baja adalah perpaduan yang sangat kuat, sehingga beton bertulang banyak digunakan sebagai bahan bangunan. Dalam kenyataannya, tulangan pada struktur beton berfungsi sebagai penahan gaya yang terjadi diatas beton tersebut.Struktur beton tidak mampu untuk menahan gaya tarik, oleh karena itu pada setiap balok -balok beton diberikan tulangan - tulangan yang dapat menahan gaya tarik tersebut. Pengujian beton yang digunakan pada penelitian ini adalah beton kubus dan balok dengan kuat tekan rencana 25 MPa. dengan tulangan besi baja 6 mm untuk sengkang dan 10 mm untuk tulangan utama dan mempunyai panjang 120x15x10 cm. Untuk mendeteksi kuat tekan yang lebih cepat, maka dilakukan pengujian pada umur 7 hari, hingga pada umur 28 hari sesuai dengan spesifikasi. Dari hasil penelitian didapat : (1) Balok bertulang dengan tulangan tanpa sambungan mempunyai nilai kekakuan rata-rata sebesar 175,704 kg/mm, (2) Balok bertulang dengan tulangan mempunyai sambungan tanpa kait pada kedua ujung mempunyai nilai kekakuan rata-rata sebesar : 160,872 kg/mm, (3) Nilai kekakuan dari beton tulangan tanpa menggunakan sambungan dengan beton tulangan yang menggunakan sambungan tanpa kait pada kedua ujung mempunyai perbedaan kurang lebih 8,38 % lebih besar beton tulangan tanpa sambungan. Hal ini disebabkan dari pengaruh tulangan baja yang sudah tidak murni utuh sehingga mengurangi kekuatan dari baja tersebut.

Jurnal Teknik Sipil Bandar Lampung, Oct 31, 2014

Universitas Bandar Lampung, Apr 30, 2015

Universitas Bandar Lampung, Apr 30, 2013

Lampung (UBL) diterbitkan 2 (dua) kali dalam setahun yaitu pada bulan Oktober dan bulan April

VISIONIST, Sep 30, 2012

Technical manager official at government administration is a middle manager that gives priority t... more Technical manager official at government administration is a middle manager that gives priority to decision making accuracy and speed. Beside of that, he must be able to translate strategic policy to operational policy and solve the operational obstacles that happened. This research aims to analyze factors that affect the speed of decision making as a foundation to formulate the strategy of implementation action. Factors that affect the performance of technical superviser to make a decision are technical training and working motivation. These factors are usually given by technical manager official . The result of this research shows that technical training and working motivation significantly affect the decision making accuracy which determinat coeficient is 88.5%. If the technical training and working motivation is increased, it will increase the performance of technical supervisor 78,3 % per year. Pejabat Pelaksana Teknis Kegiatan pada birokrasi pemerintah adalah manajer menengah yang mengutamakan ketepatan dan kecepatan pengambilan keputusan. Selain itu harus mampu menterjemahkan kebijakan strategis menjadikan kebijakan operasional, juga harus mampu memecahkan masalah operasional yang ada. Riset ini bertujuan untuk menganalisis faktor-faktor yang mempengaruhi ketepatan pengambilan keputusan sebagai dasar untuk merumuskan strategi Pelaksanaan Pekerjaan. Dua variabel utama yang mempengaruhi kinerja tenaga pengawas teknis dalam pengambilan keputusan yaitu Pelatihan Teknis dan Motivasi Kerja yang diberikan Pejabat Pelaksana Teknis Kegiatan. Dari hasil penelitian diketahui bahwa kedua faktor tersebut secara signifikan berpengaruh terhadap ketepatan pengambilan keputusan dengan nilai koefisien determinasi sebesar 88,5 %. Bilamana Pelatihan Teknis dan Motivasi Kerja ditingkatkan, maka skala Kinerja pengawas Teknis dapat meningkat sebesar 78,3 % dalam satu tahun.

Universitas Bandar Lampung, Oct 31, 2016

Bacterial populations that colonize a host play important roles in host health, including serving... more Bacterial populations that colonize a host play important roles in host health, including serving as a reservoir that transmits to other hosts and from which invasive strains emerge, thus emphasizing the importance of understanding rates of acquisition and clearance of colonizing populations. Studies of colonization dynamics have been based on assessment of whether serial samples represent a single population or distinct colonization events. A common solution to estimate acquisition and clearance rates is to use a fixed genetic distance threshold. However, this approach is often inadequate to account for the diversity of the underlying within-host evolving population, the time intervals between consecutive measurements, and the uncertainty in the estimated acquisition and clearance rates. Here, we summarize recently submitted work [14] and present a Bayesian model that provides probabilities of whether two strains should be considered the same, allowing to determine bacterial clearance and acquisition from genomes sampled over time. We explicitly model the within-host variation using population genetic simulation, and the inference is done by combining information from multiple data sources by using a combination of Approximate Bayesian Computation (ABC) and Markov Chain Monte Carlo (MCMC). We use the method to analyse a collection of methicillin resistant Staphylococcus aureus (MRSA) isolates.

Jurnal Teknik Sipil Bandar Lampung, Oct 31, 2015

Engineering Solid Mechanics, 2022

Nowadays, with increased demand for aggregates for concrete and an awareness of the need of prote... more Nowadays, with increased demand for aggregates for concrete and an awareness of the need of protecting natural resources, experts are becoming increasingly interested in waste material as a building material substitute. However, the compressive strength is influenced by the composition of concrete. In this study, the compressive strength of concrete under substitution using waste from cockle shells and glass was investigated using Response Surface Methodology (RSM). Central Composite Design (CCD) based on RSM was used to assess the influence of epoxy resin, cockle shells powder, and glass powder on compressive strength responses. RSM developed first-order and second-order mathematical models with findings from experimental design. Analysis of variance was used to determine the correctness of CCD's mathematical models. Desirability analysis was then employed to optimize epoxy resin, cockle shells powder, and glass powder yielding maximum compressive strength. The RSM analysis rev...

Abstract- The strength and durability of concrete depends on the composition of its constituent m... more Abstract- The strength and durability of concrete depends on the composition of its constituent materials ie fine aggregate, coarse aggregate, cement, water and other additives. The cement composition is about 10 % acting as a binder paste material fine and coarse aggregates. In the Lampung market there are several brands of portland cement used by the community to make concrete construction. Although there is a standard of the government of portland cement composition, yet each brand of cement has different characteristics. Cement is generally composed of limestone / limestone containing calcium oxide (CaO), clay (clay) containing silica oxide (SiO2), aluminum oxide (Al2O3), iron oxide (Fe2O3) and a cast that serves to control the hardening. Cement manufacturers make products based on chemical elements resulting from the research to make their products better than other products, so although procedurally similar but have different composition and properties. Another difference are ...

Use of false beams on reinforced concrete slab instead of the joist is an innovation in the const... more Use of false beams on reinforced concrete slab instead of the joist is an innovation in the construction of reinforced concrete slab. Where the study was made by using 4 samples of precast concrete slab specimens (PBP). Ie: P1 type - plate only, type P2 - plate with joists, type P3 - small plates with slight beams, type P4 - plate with big apparent beam. The fourth specimen samples made using the Batu Raja cement, sand from Gunung Sugih, and local split Bandar Lampung in the Civil Engineering Laboratory of UBL. The fourth test specimen samples was conducted at the Laboratory of Civil Engineering Unila using method one point load that is placed in the center - the center span in order to get the load and the maximum deflection and crack patterns. The data obtained are used to verify the theoretical calculations. Conclusions will be given at the end of writing.

International journal of engineering science and technology, 2013

This research aims at determining the behaviour of structural elements of precast reinforced conc... more This research aims at determining the behaviour of structural elements of precast reinforced concrete beams which are connected with wet and dry connections. Specimen used was 30 Mpa reinforced concrete beams with 6 pieces of 8 mm diameter main reinforcement which are placed on two rollers at the joint pedestal of each end and has a rectangular cross section of prismatic 10x18 cm2. Wet connection is a connection that uses a polymer concrete material of 40 MPa with a grafting method using prepacked method. The result of the research is expected to contribute to the development of precast concrete in building construction in Indonesia. In the elastic condition, the beam monolith has the largest natural frequency of the value, but a wet connection beam has a low natural frequency value. The difference of this natural frequency value is also equal to the condition of crack and ultimate.

Hydration, methylation and spermine binding drastically affect the conformation and behavior of d... more Hydration, methylation and spermine binding drastically affect the conformation and behavior of duplex DNA oligomers. Ciystallographic analysis of eight DNA octamers that crystallize isomorphously as A DNA in the tetragonal space group P43212, reveals a strong dependence of their major groove hydration on local helix parameters. Increased states of hydration are correlated with high twist angles, negative base rolls, and GC base pairs. Local helix geometry also has qualitative effects on the hydration patterns in the major grooves of the tetragonal A DNA octamers. A second regulator of DNA conformation is spermine, which has been found in the crystal lattices of the tightly packed A DNA decamers d(CCGGGCCCGG) and d(CCGGGCCMcCGG). Ordered spermines are located in regions of high phosphate density and, consequently, facilitate the condensation, bending and twisting of duplex DNA. The methylated derivative has been crystallized in three different conformational states and two crystal s...

This study is known as the Bamboo Concrete Beams (B3) with bamboo casing as an alternative reinfo... more This study is known as the Bamboo Concrete Beams (B3) with bamboo casing as an alternative reinforcement, conducted through experimental methods. The test results were then verified through analytical calculations. Behaviors examined included mechanical properties of bending, beam flexural strength and fracture patterns are burdened by the quasi-static load. Researchers used 16 pieces of the test specimen. Bamboo specimens used in this study is a type of Petung Bamboo (Dendrocalamus Asper), with a long piece of bamboo varies from 2860 mm to 3910 mm, outer diameter of the bottom of the 105 mm to 155 mm and the outer diameter of the upper section of 95 mm to 135 mm, which are grouped into 5 kinds of testing that is,1. Bamboo intact, the inner segments remain, with BA code (2 pieces of the specimen)2. Bamboo intact, the inner segments removed, the code BP (2 pieces of the specimen)3. Bamboo shoots in a section removed (like bamboo pipes) and not given a bamboo rod stud, with code BTS (...

Journal of Aerospace Computing Information and Communication, 2013

Civil and Environmental Research, 2019

Slab without beams cause bending cracks in the tensile region at a low loading level. One way to ... more Slab without beams cause bending cracks in the tensile region at a low loading level. One way to overcome these weaknesses is to provide a pre-concentric or eccentric initial bias style. In this study, we wanted to compare the performance of prestressed concrete slabs in terms of cross-sectional strength capacity and rigidity of concrete slab without prestressing through experiments. Objects that were tested without prestressing were made 1 piece, namely P1, and objects that were tested with prestressing were 3 piecesnamely P2 with 2 tendons, P3 with 3 tendons, and P4 with 4 tendons. The dimensions of each object tested are 100 × 40 × 8 cm and all of them are designed with concrete qualityf'c = 30 Mpa. The tendon usedis 8 mm plains teel that is pulled by tightening the nuts at both ends, with a parabolic profile shape and eccentricity value in the middle span of 1.5 cm. From the test results obtained a very significant increase in the crosssectional strength capacity of specimens P2, P3 and P4 against P1. The increase in peak load that can be borne by 192.18% is for P2, 286.54% is for P3, and 383.00% is for P4. It also happened to increase the peak bending moment which can be borne by 161.57% for P2, 241.05% for P3, and 322.68% for P4.