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Salah satu tantangan utama pada saat proses pemulihan setelah kejadian bencana gempa adalah proses perbaikan tempat tinggal masyarakat. Setelah masa darurat selesai dan masyarakat kembali dari tempat pengungsian, mereka kembali ke rumahnya yang sudah rusak bahkan hancur berantakan. Pada tahap seperti ini masyarakat berada dalam situasi kebingungan dan kurang pasti harus melakukan apa. Tulisan dalam artikel ini ditujukan untuk memberikan pengetahuan kepada masyarakat bagaimana cara membangun kembali rumahnya dari puing-puing bekas yang tersisa dan bahan bangunan yang ada disekitarnya. Konsep yang ditawarkan disini adalah sebuah desain rumah yang masih termasuk dalam katagori hunian sementara (huntara) tetapi bisa memenuhi semua kebutuhan dasar penghuni layaknya sebuah rumah tinggal dan bisa ditempati dalam waktu tahunan sampai masyarakat siap membangun kembali rumahnya secara permanen. Bahan yang digunakan adalah bahan yang tersedia disekitar lingkungan pemukiman dan beberapa bagian merupakan daur ulang dari puing-puing bekas rumah yang mengalami kerusakan. Konsep hunian sementara ini telah berhasil didesain, dibangun dan diaplikasikan

Kerusakan dan kerugian terbesar yang diakibatkan oleh gempa Lombok tahun 2018 di Kabupaten Lombok Utara adalah sektor permukiman yaitu sebesar 72,43 % dengan total rumah rusak sebanyak 63.332 unit. Desa Karang Bajo adalah salah satu desa di Kecamatan Bayan Kabupaten Lombok Utara dimana terdapat cukup banyak rumah warga yang mengalami kerusakan dengan katagori sedang dan berat pasca gempa tahun 2018. Permasalahan yang ditemui bahwa masih banyak masyarakat yang belum mengetahui bagaimana cara membuat bangunan yang lebih tahan terhadap gempa ditinjau dari aspek struktural. Disisi lain, potensi tanaman bambu di Kecamatan Bayan cukup banyak namun pemanfaatannya belum optimal khususnya untuk membuat rumah yang aman dari gempa bumi. Dengan demikian penyuluhan tentang pembangunan rumah dari pasangan batu maupun rumah dari bambu plester yang tahan gempa ini sangat relevan dengan kebutuhan masyarakat di Desa Karang Bajo. Metode kegiatan yang dilaksanakan dikemas dalam bentuk demo dan penyuluhan. Demo dilakukan untuk menjelaskan secara langsung bagaimana cara membuat rumah dari pasangan batu dengan struktur beton bertulang dan rumah bambu plester yang tahan gempa. Adapun kegiatan penyuluhan ini dibagi menjadi beberapa tahap yaitu persiapan penyuluhan, pembuatan materi dan gambar-gambar desain sebagai alat bantu penyuluhan, koordinasi dengan Kepala Desa dan menentukan jadwal dan lokasi/tempat penyuluhan. Dari hasil penyuluhan terlihat bahwa masyarakat desa Karang Bajo telah mendapatkan informasi dan pengetahuan tentang bangunan sederhana tahan gempa dari beton bertulang dan bambu plester. Dengan pengetahuan yang dimiliki diharapkan dapat ditularkan kepada keluarga dekat dan masyarakat disekitarnya

Kajian mengenai komposit polimer - serat alam yang sering ditampilkan oleh para peneliti lebih banyak didasarkan pada kondisi lingkungan normal. Padahal dalam kenyataannya, penggunaan material komposit seringkali berada atau dihadapkan pada situasi yang tidak normal atau agresif seperti kelembaban dan temperatur yang selalu berubah. Tujuan dari penelitian ini adalah untuk melakukan evaluasi terhadap sifat mekanik komposit yang diperkuat dengan serat alam – abaka dan rami - yang ditempatkan pada lingkungan yang agresif. Penelitian dilakukan secara eksperimental dimana tiga jenis lingkungan agresif; ruang terbuka, air laut dan ditanam dalam tanah menjadi variabel penelitian. Sebagai pembanding atau kontrol, komposit juga ditempatkan pada ruang tertutup dengan kondisi normal. Setelah diekspose selama 8 minggu, sampel komposit kemudian dipersiapkan untuk diuji kekuatan tarik dan lenturnya. Progress dari proses degradasi komposit juga dievaluasi setiap minggu. Secara umum hasil penelitian menunjukan bahwa ekspose pada lingkungan agresif belum memberikan pengaruh yang signifikan pada sifat fisik maupun mekanik komposit. Pada observasi yang dilakukan terhadap komposit poliester-rami, terlihat bahwa ekspose pada lingkungan agresif mengurangi kekuatan tarik dan lentur komposit. Tetapi pada pengujian yang dilakukan terhadap komposit poliester-rami, justru terjadi sebaliknya dimana kekuatan tarik dan lentur komposit yang diekspose pada lingkungan agresif lebih tinggi dibandingkan dengan kontrolnya, yakni komposit yang tidak diekspose pada lingkungan agresif. Sangat besar kemungkinan bahwa karena komposit poliester-rami yang dijadikan sebagai kontrol memiliki banyak rongga, maka sifat mekaniknya sudah lebih rendah daripada komposit yang diekspose pada lingkungan agresif.

Pada tahun 2018 terjadi gempa bumi di Provinsi Nusa Tenggara Barat, gempa ini diawali pada tanggal 28 Juli 2018 dengan kekuatan Magnitude 6,5 SR yang kemudian diikuti puluhan gempa susulan, setelah itu gempa yang signifikan terjadi lagi pada tanggal 5 Agustus 2018 dengan kekuatan Magnitude 6,9 SR. Salah satu daerah yang mengalami kerusakan berat yaitu Kabupaten Lombok Utara, namun penanganan perbaikan infrstruktur terutama subsektor perumahan pasca bencana mengalami keterlambatan, yang sampai saat ini belum terselesaikan di wilayah ini. Adapun tujuan dalam penelitian ini yaitu mengetahui pelaksanaan di lapangan dan strategi yang optimal sehingga mempercepat pemulihan infrastruktur subsektor perumahan dengan menggunakan metode AHP dan SWOT. Analisa AHP menggunakan teknik purposive sampling yaitu dengan pertimbangan tertentu. Sedangkan, analisis SWOT menggunakan teknik proportionate stratified random sampling yaitu pengambilan sampel dari anggota populasi secara acak dan berstrata secara proporsional. Dari hasil dan pembahasan diperoleh strategi alternatif menggunakan metode SWOT dengan analisis matriks IFAS dan EFAS, untuk grand strategi masuk dalam kuadran III yaitu strategi W-O (Weakness-Opportunity). Kemudian, alternatif strategi SWOT dengan antar kriteria yang dianalisis menggunakan AHP diperoleh bobot nilai Global Priorty yaitu Alternatif 1 = 36,3%, Alternatif 2 = 31,6%, selanjutnya Alternatif 3 = 32,2%. Pelibatan masyarakat dalam proses rehabilitasi dan rekonstruksi baik dalam penentuan kebijakan serta pelaksanaan di lapangan menjadi strategi optimal dalam penanganan rehabilitasi dan rekonstruksi subsektor perumahan pasca gempa bumi NTB 2018 di Kabupaten Lombok Utara.

Kepulauan Indonesia merupakan wilayah yang rawan terjadi bencana geologi khususnya gempa bumi dan tsunami karena terletak pada pertemuan tiga lempeng dunia yaitu lempeng Eurasia, lempeng Indo-Australia dan lempeng Samudera Pasifika yang biasa disebut ring of fire. Pulau Lombok dan Sumbawa, berada pada posisi yang dekat dengan pertemuan dua lempeng tersebut yaitu Lempeng Indo-Australia di bagian selatan dan Lempeng Eurasia. Mengingat banyaknya korban jiwa dan bangunan rumah yang rusak atau hancur maka pada saat terjadi gempa di daerah yang berdampak sebagai lokasi mitra dalam hal ini Desa Gondang Kecamatan Gangga Kabupaten Lombok Utara, maka kegiatan ini bertujuan memberikan pengetahuan kepada masyarakat dan para tukang khususnya tentang bagaimana cara merencanakan suatu bangunan yang aman terhadap bahaya gempa dengan inovasi balutan ferosemen pada tembok tanpa memakai besi tulangan sebagaiman biasanya. Metode pelaksanaan dilakukan dengan dengan pejelasan tentang dasar-dasar pembuatan rumah atau bangunan tahan gempa dengan inovasi balutan ferosemen dan diakhir dengan praktek atau demo pembuatan tembok bata dengan mengaplikasikan balutan ferosemen untuk meningkatkan ketahanan terhadap bahaya gempa. Saat kegiatan pelatihan warga Desa Gondang sangat antusias mengikuti acara sampai selesai. Tingkat partisipasi masyarakat mencapai hampir 100% kehadiran dari yang diundang menghadiri acara workshop.

The advantages of using self-compacting concrete (SCC) are reducing the time of construction and the number of employments, reducing noise that can disturb the surrounding environment, and increasing the density of hardened concrete structural elements, automatically affecting bond strength reinforcement in SCC. The bond strength is a parameter as an essential factor affecting the behavior of reinforced concrete. In this manuscript, the Adaptive Neuro-Fuzzy Inference System (ANFIS) model was built to predict the bond strength in SCC. For showing the performance of the ANFIS model, the level of accuracy-based correlation coefficient (R2) and Root Mean Square Error (RMSE) were determined. Learning process data consists of input and output. The input in this study includes compressive strength of concrete (f'c), the diameter of steel reinforcement (db), and development of length (Ld), while the output bond strength ( ). The results of the proposed model were in good agreement with the experimental results, as evidenced by an R2 of 0.71 and an RMSE of 3.31 MPa in the testing data, indicating that the proposed ANFIS model is capable of accurately predicting steel reinforcement bond strength in SCC.

Dusun Lebah Sari adalah salah satu dusun di Kecamatan Pemenang yang rusak parah akibat gempa Lombok 2018. Kerusakan yang masif mengharuskan warga membangun dan menata kembali pemukiman mereka termasuk fasilitas pribadi seperti jamban. Momen penataan kembali inilah yang ingin dimanfaatkan oleh tim untuk memberikan pemahaman khususnya kepada para pekerja konstruksi atau tukang bangunan dengan cara penyuluhan guna mentransfer pengetahuan tentang pembuatan tangki septik yang baik dan sesuai Standar Nasional Indonesia. Mengingat desa ini sedang merintis jalan menjadi desa ekowisata yang menjual keindahan pemandangan alam termasuk fasilitasnya, maka kesehatan dan kenyamanan lingkungan harus diperhatikan. Kegiatan yang dihadiri oleh kepala dusun, tokoh masyarakat, pemuda dan ibu-ibu ini berjalan dengan lancar. Peserta sangat antusias mengikuti penjelasan Tim dan berkonsultasi pada sesi tanya jawab. Kegiatan ini diharapkan dapat menjadi kontribusi aktif Perguruan Tinggi terhadap penyelesaian salah satu potensi permasalahan lingkungan khususnya bagi masyarakat dusun Lebah Sari demi penataan kembali pemukiman dan lingkungan yang lebih baik

This study aims to investigate the impact and compressive strength properties of corn husk fibre (CHF)/polyester composites. The composites were subjected to water immersion treatment at two different durations. A polyester mixture with CHF of different fibre volume fractions was formed via hot press at 107 °C for 5 min. All composites were soaked in water for 24 and 72 h. Characterisation of impact and compressive strength, water absorption and thickness swelling properties of the composites were evaluated. The morphology of surface fractures of the composites was also analysed using scanning electron microscopy (SEM). Results show that the impact and compressive strength, thickness swelling and water absorption properties of the composites initially increased after 24 h of dyeing treatment. After soaking for 72 h, the moisture absorption and swellability properties of each composite increased by approximately 0.24%–1.38% and 0.08%–1.04%, respectively. Consequently, the impact strength of the composites increased, but the compressive strength decreased due to the weakened interface of polyester–fibres. SEM images show the interface between the fibres and the spread of fibres and voids. These results indicate that CHF composites can be an alternative for wood composites as construction materials.

A long series of earthquakes that lasted for almost a month with the biggest shock reaching 7 SR completely destroyed most of the houses in parts of Lombok and Sumbawa. Many residents were forced to evacuate because their homes entirely devastated. Some residents have returned to their homes, but many also have no place to return. So they need temporary shelter while rebuilding their houses gradually. There are many choices of designs that have been developed before. However, designing a temporary shelter that is truly in accordance with the needs of the community at the disaster site requires a comprehensive understanding of the local human characteristics and nature as well as the local environment. Including things that must be considered is the impact on the environment if the design involves locally available nature material. The design concept was based on the concept of a barn house with bamboo and spandex-plywood materials. The first concept is a bamboo barn shelter which adopts a traditional Lombok house with woven bamboo walls. The second concept is also based on traditional Lombok houses, but uses a different material which is spandek as the dominant material for the roof and plywood as the walls and doors. Both temporary shelter concepts have been successfully designed, built and applied.

Provinsi Nusa Tenggara Barat (NTB), yang terdiri dari Pulau Lombok dan Sumbawa, berada pada posisi yang dekat dengan pertemuan dua lempeng yaitu Lempeng Indo-Australia di bagian selatan dan Lempeng Eurasia di bagian utara. Pada tempat pertemuan lempeng tersebut, yang dikenal dengan nama zona subduksi, terjadi tumbukan/pergesekan yang dapat menjadi sumber terjadinya letusan gunung api, gempa bumi dan tsunami. Pada Tahun 2018, bencana gempa bumipun terjadi yang berpusat pada Kecamatan Kayangan Kabupaten Lombok Utara. Menurut laporan BNPB (2018), bencana gempa bumi tersebut memakan korban jiwa, baik meninggal maupun luka luka. Pada daerah terdampak tersebut, diperlukan pengetahuan tentang bagaimana cara merencanakan suatu bangunan yang aman terhadap bahaya gempa. Dalam hal ini akan disampaikan panduan teknis langkah-langkah merencanakan, mendesain dan melaksanakan suatu bangunan yang aman terhadap gempa bumi. Disamping itu akan diberikan pemahaman bagaiman cara memperbaiki rumah tembok yang mengalami kerusakan ringan sampai sedang agar bisa berfungsi sebagai rumah yang aman terhadap gempa mengacu ke juknis dari Kementerian PU, Dirjen Cipta Karya (2006)

When wood structures are exposed to high temperatures, they will decompose to provide a char layer and pyrolysis zone, an insulating material that inhibits further degradation. This experimental study aims to determine the char thickness and pyrolysis of solid wood exposed to fire for 30, 45, and 60 minutes. The post-fire shear strength has also been evaluated. The solid woods were locally from Nusa Tenggara Island, namely Jati Putih, Bajur, and Rajumas. According to the Indonesian National Standard of the heating curve for structures, the temperature growth was SNI-1741: 2008. Obtained The char layer's highest average thickness was within 60 minutes of combustion with the highest temperature of 1055oC. The char layer for Jati Putih, Bajur, and Rajumas are 2.12 mm, 7.89 mm, and 6.53 mm. Meanwhile, the pyrolysis layers are 8.78 mm, 9.13 mm, and 14.82 mm, respectively, for Jati Putih, Bajur, and Rajumas. Besides, the post-fire shear strength of all wood species shows an increase in shear strength in the core. Wood can still sustain the load during a fire because there is a char layer preventing the core section from immediately exposed to the fire.

Among the many choices of composite sandwich panel cores, Balsa wood is one of the main alternatives of cores made of wood. However, the availability and price of Balsa wood are quite expensive, so it needs alternatives from other types of wood such as Sengon wood. The purpose of this study was to evaluate the feasibility of Sengon wood as a core of composite sandwich panels. Three variations of the Sengon wood layout had been prepared as the core of the sandwich panels with a skin made of aluminum. All specimens, including the control specimens made of whole Sengon wood, were prepared with a size of 550 x 50 x 24 mm for length, width, and depth, respectively. Each variation and also the control specimens were made of 3 pieces. Tests were carried out based on the ASTM C 393-94 standard under the three-point bending test scheme. The results showed that the sandwich panel with plain Sengon wood core has the highest capacity to carry a flexural load, which is approximately 177.391 MPa, followed by a sandwich panel with long and end grain Sengon board that possess flexural strength of 153.913 MPa and 79.101 MPa, respectively. The flexural strength of these sandwich panels is superior to solid Sengon wood. The sandwich panels showed a typical ductile material indicated by a non-linear curve without a distinct yielded point before reach the maximum failure load. Three sandwich panels with various Sengon wood cores collapsed under three types of failure mechanisms; face wrinkling, shearing of the core, and delamination between the interface of skin and core. In conclusion, Sengon wood has a great potential to be used as the core material for a composite sandwich panel.

The combination of low price, ease of manufacturing and waterproofing characteristics has placed polyester resin as a potential sound absorbent material. Previous studies showed that adding filler material to the blending may increase the acoustics properties of a sound absorbent material. This study aims to investigate the potential of sodium bicarbonate (NaHCO3) to be employed as a filler to improve the acoustic properties of the sound absorber made of polyester resin. Two important acoustic parameters were carefully assessed; absorption coefficient and acoustic impedance. The results showed that the sound absorption performance increased significantly at low and medium frequencies in the presence of NaHCO3 filler in polyester resin. Meanwhile, the use of a back cavity on the absorbent material reduced the sound absorption performance of materials at low and medium frequencies. This suggests that sound absorber made of polyester with sodium bicarbonate filler may be used as an alternative for sound absorber materials.

This paper presents an experimental investigation on the tensile properties of lignocellulosic composites; which is specifically compare the tensile properties of composites derived from natural fibers (jute, sisal and hemp) to a medium density fiber (MDF). The study was conducted experimentally by performing tensile tests according to BS EN ISO 527-2 using a MTS machine. Five specimens were prepared for each composite laminate. The results show that the tensile properties of lignocellulosic composites derived from natural fibers are superior to medium density fiber. The tensile strength of medium density fiber is 17.1 MPa; while sisal, jute and hemp fiber composite has the value of 40.25 MPa, 37.25 MPa and 31.37 MPa, respectively. Further, medium density fiber has the elastic modulus of 2603 MPa; while jute, sisal and hemp fiber composite has the values of 4592 MPa, 3643 MPa and 3048 MPa, respectively. Natural fiber composites also possess higher Poisson’s ratio which is greater than 0.36, while medium density fiber has the value of 0.25. Keywords: Lignocellulosic composite, tensile properties, Poisson ratio, elastic modulus

Polymeric composites reinforced with natural fibers have raised more attention as the alternative building materials. In this work, natural fiber composites prepared from jute and hemp fiber were proposed for the intermediate layer of a hybrid sandwich panel. This paper presented the flexural behavior of the newly developed hybrid sandwich panel which included the comparison of the ultimate load, load-deflection behavior, load-strain behavior and failure modes. The study was designed as a single factor experiment where the performance of hybrid sandwich panels containing jute fiber composite (JFC) and hemp fiber composite (HFC) as the intermediate layer was compared to the control (CTR) which was a conventional sandwich panel without an intermediate layer. A static flexural test under a four-point bending load scheme was performed in accordance with the ASTM C 393-00 standard. Aluminium sheet was used as the skins, while expanded polystyrene (EPS) was employed for the core. The testing was performed using a 100 kN servohydraulic machine with a loading rate of 5 mm/min. The applied load, displacement and strains were obtained using data logger. The results demonstrated that the hybrid sandwich panel exhibited a more superior performance than the conventional sandwich panels. The intermediate layer contributed significantly to enhancing the load carrying capacity of the hybrid sandwich panel. The load carrying capacity of hybrid panel with the JFC intermediate layer was 29.60% higher than the conventional sandwich panel, and correspondingly 93.46% higher for the sandwich panel with the HFC intermediate layer. The hybrid sandwich panels also developed a much larger area under the load-deflection curve, indicating greater toughness. The introduction of intermediate layer helped the hybrid sandwich panels to sustain a larger strain prior to reach their ultimate loads, resulting in a higher deformation capability. Indentation and core shear were observed as the failure mode of the conventional sandwich panel. Meanwhile, core shear and delamination were identified as the failure mode of the hybrid sandwich panel. Refereed/Peer-reviewed

Sand is one of the key material in civil engineering, which is sometime overlooked during the construction process. In many projects, the first concern is about the structure and then the material. The improper use of material doesn’t show significant signs in the early stage of building service. Using low quality material may give significant impact after few years and when it comes to a concern, it’s always too late to be repaired. Sand has drawn many attentions in term of its quality and few works dealing with this topic have been reported. This study aims to asses the quality of sand collected from few government building projects in west Lombok. The results were analysed using statistic software, which is SPSS 16.0, to provide inferential analyses. A mixed model, namely field surveys and laboratory experiments, were employed for the research methodology. It was found that only one out of the seven project that used proper sandmin terms of quality. The rest do not meet the standards required by SNI (Indonesian Nasional Standard) for sand material. It was also found that the quality of sand used by the observed projects under this research was significantly differ from each other, in terms of their bulk density, apparent specific density, SSD specific density, water absorption, silt content, loose content weight, solid fill weight, and fine modulus. It is strongly recommended that the government should take a good control to the sand suppliers/providers as well as the builders especially when they are involving in the government projects.

This paper discusses the results of an experimental investigation on the shear properties of natural fibre composites using the V-Notch or Iosipescu shear test. The natural fiber composites were made of jute and hemp fibers reinforced epoxy polymer resin. The testing was conducted using an MTS machine equipped with a 10 kN load cell in accordance with the ASTM standard D5379M. The testing machine was set-up to apply a load with a speed of 2 mm/min. It was found that the jute fiber composites (JFC) have an average shear stress of 25.56 MPa, while the hemp fiber composites (HFC) have an average value of 22.46 MPa. The loaddisplacement graphs showed a nearly linear trend at the initial loading stage that slightly deflected prior to reaching the maximum load. Most of the specimens in both groups, JFC and HFC, showed fractures in a diagonal cracking pattern, known as an off-axial failure mode. Only a few specimens collapsed across the notched section. Both are customary failure modes for this type of shear test.

A large amount of waste concrete generates an environmental problem due to demolition of old concrete structures. To solve this problem, it is necessary to collect recycled aggregate from waste concrete. The conventional recycling technique of recycled aggregate from waste concrete does not indicate a significant quality to be re-used for making a new concrete. We proposed new techniques to produce high grade recycled aggregate by heating-grinding (H-G) method and heating-grinding-acid (H-G-A) method. To ensure the quality of the concrete made from recycled coarse aggregate concrete, the non-destructive evaluation was conducted in this research. High grade recycled aggregate concrete were prepared in advanced using two methods mentioned earlier. Then, new concrete specimens were produced using those types of recycled aggregate concrete. After 28 days curing time, rebound hammer test and ultrasonic pulse velocity test were performed on recycled coarse aggregate concrete to examine the surface hardness and ultrasonic wave velocity of the concrete. Almost similar quality to natural coarse aggregate in terms of density, water absorption, sieve analysis achieved by both H-G recycled coarse aggregate and H-G-A recycled coarse aggregate. However, the surface hardness and ultrasonic wave velocity of H-G-A recycled coarse aggregate concrete is better than those of H-G recycled coarse aggregate concrete. That acid solvent enables to dismantle the cement paste from aggregate surface more effectively, so this types of recycled aggregate shows a better performance than the other one. Continued delamination reduces pores in the interfacial transition zone resulting better bonding mechanism between new cement paste and recycled aggregate surface.

This paper presents a comparison of theoretical and experimental deflection of a hybrid sandwich panel under four-point bending load. The paper initially presents few basic equations developed under three-point load, followed by development of model under four-point bending load and a comparative analysis between theoretical and experimental results. It was found that the proposed model for predicting the deflection of hybrid sandwich panels provided fair agreement with the experimental values. Most of the sandwich panels showed theoretical deflection values higher than the experimental values, which is desirable in the design. It was also noticed that the introduction of intermediate layer does not contribute much to reduce the deflection of sandwich panel as the main contributor for the total deflection was the shear deformation of the core that mostly determined by the geometric of the samples and the thickness of the core. Refereed/Peer-reviewed

This paper presents the significance analysis of a new type of hybrid composite sandwich wall panel which can be manufactured as modular panelised system. Two different types of natural fibers reinforced plastics (NFRP) laminate were incorporated into the new sandwich panel as an intermediate layer. The significance analysis in this research has been carried out using analysis of variance (ANOVA). As the aim of the analysis is to select the most appropriate natural fiber composites for the intermediate layer, the experiments were arranged as a single factor experiment in which 3 levels of a factor have been examined. The factor refers to the type of intermediate layer used in the sandwich panel. The result of this study shows that the incorporation of intermediate layer has significantly enhanced the load carrying capacity of the sandwich panels. Refereed/Peer-reviewed

This paper presents a statistical aspect of experimental study on the in-plane shear behaviour of hybrid composite sandwich panel with intermediate layer. The study was aimed at providing information of how significant the contribution of intermediate layer to the in-plane shear behaviour of new developed sandwich panel. The investigation was designed as a single factor experimental design and the results were throughly analysed with statistics software; Minitab 15. The panels were tested by applying a tensile force along the diagonal of the test frame simulating pure shear using a 100 kN MTS servo-hydraulic UTM. The result shows that the incorporation of intermediate layer has sinificantly enhanced the in-plane shear behaviour of hybrid composite sandwich panel. The statistical analysis shows that the value of F0 is much higher than the value of Ftable, which has a meaning that the improvement provided by the incorporation of intermediate layer is statistically significant.

Tingkat kepadatan permukiman di Kota Mataram tidak merata. Tingkat kepadatan yang terjadi pada pusat kota sangat tinggi, ini dilihat dari meningkatnya jumlah bangunan permukiman maupun pertumbuhan penduduk yang sangat pesat. Hal ini menyebabkan terjadinya penurunan kualitas infrastruktur karena jumlah permukiman tidak diimbangi dengan peningkatan infrastruktur, sedangkan kawasan permukiman di pinggiran kota yang diharapkan menjadi kota baru banyak yang akhirnya gagal karena kurangnya atau bahkan tidak adanya infrastruktur yang mendukung. Tujuan dari penelitian ini adalah untuk mengidentifikasi ketersediaan infrastruktur yang ada pada saat ini dan mengetahui hubungan antara ketersediaan infrastruktur dengan tingkat kepadatan permukiman. Metode pengambilan data adalah dengan menggunakan kuesioner. Sedangkan untuk menganalisis data, menggunakan analisis jalur yang berguna untuk mengetahui hubungan antara ketersediaan infrastruktur dengan tingkat kepadatan permukiman. Hasil identifikasi ketersediaan infrastruktur diketahui bahwa untuk ketersediaan infrastruktur pada saat ini masih tidak memperhatikan tingkat kepadatan permukiman. Dari hasil analisis data diketahui bahwa a) Ketersediaan infrastruktur jalan memiliki korelasi langsung dengan tingkat kepadatan permukiman; b) Ketersediaan infrastruktur sanitasi/ air limbah tidak memiliki korelasi langsung dengan tingkat kepadatan permukiman; c) Ketersediaan infrastruktur persampahan memiliki korelasi langsung dengan tingkat kepadatan permukiman; d) Ketersediaan infrastruktur drainase memiliki korelasi langsung dengan tingkat kepadatan permukiman. 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In this study, three different types of lignocellulosic composite materials have been incorporated in sandwich panel structure as an intermediate layer. The experiment was statistically designed based on single factor analysis scheme. The results of experiments have been analyzed using analysis of variance (Anova) followed by Tukey's, Fisher's and Dunnet's tests to obtain the information of how significant those materials contribute to the flexural strength of sandwich panel structure. The total number of samples tested was 48 beams. The results show that the introduction of lignocellulosic composites materials, that are hardboard, medium density fibre (MDF) and plywood, has significantly improved the flexural strength of sandwich panel. The range of improvement contributed by the presence of lignocellulosic composites intermediate layer was around 100-150% for samples with balsa core and 130-150% for samples with polystyrene core. The result of this study shows the potential of lignocellulosic composite material to be developed further for producing more sustainable sandwich panel. Refereed/Peer-reviewed

The study reported here involves the evaluation of the ultimate bending stress (bending strength) of hybrid sandwich panels using a simple comparative statistical analysis. Four sets of beam were tested with each set consisting of modified beams (MB) and unmodified beam (UB) samples. A total of 42 beam samples were tested using 3 point bending followed by statistical inference analysis using a t-test. The results show that the introduction of an intermediate layer has a significant effect on increasing the bending strength of the new hybrid sandwich panel composite. Refereed/Peer-reviewed

In this paper, we present a comprehensive analytical and experimental investigation for the determination of the air flow resistivity and porosity of sound absorber composite. The ratio of the volume fraction of fiber and polyester resin is 15, 25, 35, 55 and 65 (%).The dimensions of the absorbent composite sample are 29 mm x 20 cm (diameter x thickness). Porosity and Air flow resistivity of composites have been investigated. The results showed that the porosity of the composites increased with increasing amount of fiber due to the interface between fiber and resinless dense. In contrast, the air flow resistivity values are lower with a denser resin and fiber interface.

This paper presents the structural behavior of newly-developed hybrid structural insulated panels (SIPs) formed by incorporating lignocellulosic composites-jute fiber composite (JFC) and medium-density fiber (MDF)-as intermediate layers between aluminum skin and an expanded polystyrene (EPS) core. The investigation was conducted as an experimental work. A four-point bending load was performed to create pure bending conditions, and the samples were prepared in accordance with ASTM C 393-00 standards. Testing was performed using a 100 kN servo-hydraulic machine with a loading rate of 5 mm/min. The results show that the incorporation of intermediate JFC or MDF layers enhanced the flexural behavior of the SIPs. The ultimate loads of hybrid SIPs with JFCs or MDF were, respectively, approximately 62.59% and 168.58% higher than the ultimate load achieved by SIPs without intermediate layers. Hybrid SIPs exhibited a much larger area under the load-deflection curve than those of conventional SIPs; this points to the toughness of the material and its ability to sustain larger compression strain prior to reaching their ultimate loads, which prevents them from prematurely failing under buckling or indentation. Refereed/Peer-reviewed

Sebagai bahan bangunan yang relatif masih baru, komposisi bahan penyusun bata non-bakar masih menjadi topik yang menarik untuk diteliti. Pada beberapa studi sebelumnya upaya mencari komposisi optimum campuran bata non bakar menggunakan metode eksperimen yang mengevaluasi pengaruh sebuah faktor dalam satu kali eksperimen atau yang dikenal dengan istilah single factor experiment. Kelemahan dari metode eksperimen ini adalah kesimpulan yang dihasilkan hanya terkait dengan satu faktor yang diamati itu saja. Sementara dalam kenyataannya, hasil dari sebuah proses tidak hanya dipengaruhi oleh satu faktor saja melainkan dipengaruhi oleh banyak faktor termasuk interaksinya. Studi ini dilakukan untuk mencari komposisi optimum bahan penyusun bata non bakar dengan menerapkan metode respon permukaan (Response Surface Method). Proses analisa data dilakukan dengan menggunakan software Minitab 17. Hasil penelitian menunjukan bahwa proporsi bahan yang menghasilkan kuat tekan paling optimal adalah semen (21,034%), pasir (28,9651%) dan tanah liat (50%), yang mampu menghasilkan bata non bakar dengan kuat tekan rata-rata sebesar 50.22 kg/cm2. Hasil penelitian ini juga merekomendasikan sebuah persamaan umum untuk memprediksi kuat tekan bata non bakar apabila menggunakan ketiga komposisi bahan tersebut, yaitu: y=-5,56x1+0,141x2+0,541x3+0,214x1 x2+0,0473x1 x_x-0,307x2 dengan x1, x2 dan x3 masing-masing adalah proporsi semen, pasir dan tanah liat.

Penelitian yang berkaitan dengan penambahan bahan pozolan untuk memperbaiki mutu mortar atau beton sudah cukup banyak dilakukan. Namun demikian, penelitian-penelitian terdahulu umumnya dilakukan dengan menggunakan metode yang berbasis pada standar. Kelemahan metode ini adalah kesimpulan yang diambil hanya berdasarkan statistik deskriptif tanpa melibatkan proses pengujian hipotesis menggunakan statistik inferensial. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh penambahan bahan pozolan silica fume terhadap karakteristik fisik dan mekanik mortar dengan mengaplikasikan metode analysis of variance (ANOVA). Metode yang digunakan dalam penelitian ini adalah metode eksperimen murni dimana percobaan laboratoriumnya didesain sebagai single factor experiment. Kesimpulan yang bisa diambil dari penelitian adalah: 1) Penambahan bahan pozolan silica fume mampu membuat mortar menjadi lebih kedap air yang ditandai dengan menurunnya daya serap air seiring dengan bertambahnya proporsi silica fume sebagai pengganti sebagian semen. Terjadi penurunan daya serap air sebesar 18,3% ketika mortar diberi tambahan silica fume sebesar 3% dari berat semen. Selanjutnya terjadi penurunan secara konstan sebesar 22,7%, 33,2% dan 35,2% ketika ditambahkan silica fume sebesar 5, 7 dan 10%. 2) Penambahan silica fume juga mampu menurunkan pH mortar. Tetapi pada penelitian ini, meskipun pH mortar menurun dengan bertambahnya proporsi silica fume, kondisi pH nya masih dalam keadaan basa yang relatif aman bagi tulangan yang dilindungi oleh mortar. 3) Untuk sifat mekanik, terlihat bahwa kuat tekan mortar berbanding lurus dengan peningkatan kandungan silica fume yang dicampurkan. Rata-rata kuat tekan mortar normal tanpa campuran silica fume adalah 39,9 MPa. Sementara kuat tekan rata-rata mortar dengan campuran silica fume secara berturut–turut adalah 40,4 MPa, 42,3 MPa, 43,2 MPa dan 45,1 MPa atau terjadi peningkatan kuat tekan berturut-turut sebesar 1,1%, 5,9%, 8,2%, dan 12,8 % untuk proporsi 3, 5, 7 dan 10%.Kata Kunci: mortar, silica fume, analysis of variance, karakteristik mortar, single factor analysis

A concept of hybrid sandwich panel with intermediate layer has been introduced previously that capable of improving load carrying capacity of composite sandwich panel. While the previous work employed numerical and experimental investigation, the current paper more focuses on developing the theoretical frameworks of the hybrid sandwich panel by using analytical model. The vocal point of the concept is introducing a new layer in between the skin and the core of a standard sandwich panel structure to form a hybrid structure. The paper begins with elaborating the basic concept of sandwich panel which includes the elastic and shear stresses in sandwich panel and followed by the deflection of sandwich panel. The next stage comprehensively highlights the theoretical concept of the hybrid sandwich panel. It was clearly shown through the developed theoretical frameworks that the incorporation of intermediate layer can substantially increase the flexural rigidity and stiffnesses which finally enhances the load carrying capacity of the new developed sandwich panel.Keywords : sandwich panel, hybrid concept, intermediate layer, analytical model.