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Non-compliant (NC) structures are often encountered in building construction in developing countries. This is a condition whereby erected buildings do not follow regulatory standards, especially in the provision of reinforcements. Therefore, under an earthquake load, the structures do not have sufficient resistance against such load. The structural elements of the building, which often have NC conditions, are the beam-column joints because they do not contain adequate shear reinforcements due to installation difficulty. This study aims to determine the structural performance of the reinforced concrete (RC) frame, which has a reinforcement deficiency in the beam-column joints. Numerical simulation was conducted on the Kakaletsis structure model by modifying the reinforcement details at the joints to represent the NC conditions. The non-linear modeling and analysis of the structural model were carried out using ATENA software. The analysis showed that the reduction in shear reinforcements in the NC model joint caused a decrease in load-carrying capacity by about 26.04%. A shift was also observed in the collapse pattern, i.e., from the beam to the end of the column, causing global failure and reducing the undamaged but increasing more severely damaged condition. This showed that the NC structure, due to the non-conformance of reinforcement, significantly reduced the structure's performance.

A primary current focus in concrete shear design is how to ensure the shear resistance of the concrete structures to withstand the possible adverse creep effects during the service life. All shear-carrying actions are supposed to depreciate due to the enhanced critical shear cracks under sustained loads. However, only a few studies that evaluated the performance of concrete structures failing in shear due to long-term loading. As the longitudinal tensile reinforcement strain influences the shear strength of RC beam, the shear resistance of the beam under sustained load may also be affected by the amount of longitudinal reinforcement. The present study aims at investigating the influence of flexural reinforcement ratio on the shear creep failures of reinforced concrete (RC) beams without stirrups by non-linear finite element analysis. In this study, the numerical model of RC beams with reinforcement ratios varying from 0.4% to 3.2% was evaluated under different loading rates. A loading rate of 1000 and 10000 times slower than the static loading rate were adopted to reveal the creep effects of RC beams.

Semen merupakan produk yang paling banyak digunakan kedua setelah air di dunia. Meningkatnya infrastruktur membuat kebutuhan semen semakin meningkat. Meningkatnya permintaan akan semen, maka diperlukan inovasi beton yang dapat mengurangi kebutuhan semen agar mengurangi pencemaran lingkungan. Salah satu inovasi yang dikembangkan saat ini adalah beton High Volume Fly Ash (HVFA) dan beton Self Compacting Concrete (SCC). Beton High Volume Fly Ash (HVFA) adalah beton yang mengandung fly ash sebagai substituent semen dengan minimal kadar yang tergantikan adalah 50% dari berat total binder. Metode penelitianyang digunakan adalah metode eksperimental dengan tempat pengujian di Laboratorium Bahan Konstruksi dan Struktur program studi Teknik Sipil Fakultas Teknik Universitas Sebelas Maret. Sampel benda uji yang digunakan berupa balok beton bertulang dengan dimensi sebesar 15 cm x 25 cm x 200 cm. Beton yang digunakan memiliki kuat tekan f’c sebesar 30 MPa dan sepsifikasi tulangan ulir dengan kuat leleh fy 405 MPa dengan panjang lewatan sepanjang 300 mm.

Kota Surakarta merupakan wilayah yang berdekatan dengan jalur lempeng Eurasia dan Indo-Australia. Ada perkiraaan dari Badan Nasional Penanggulangan Bencana (BNPB) bahwa jika terjadi gempa megathrust di pertemuan lempeng tersebut akan mengakibatkan gempa dengan kekuatan di atas 8 SR. Guna mengantisipasi segala kemungkinan buruk yang terjadi maka diperlukan kesadaran dan partisipasi aktif masyarakat, para pemangku kepentingan, dan tenaga kerja bidang konstruksi sehingga korban jiwa dan kerugian materi bisa ditekan seminimal mungkin. Waktu terjadinya gempa tidak dapat diperkirakan dengan pasti. Kota Surakarta pernah juga terdampak gempa Yogyakarta tahun 2006. Dari pengalaman tersebut tampak kesiapan mitigasi bencana gempa di beberapa wilayah terdampak sebagian besar masih kurang. Research Group SmartCrete, Program Studi Teknik Sipil, Universitas Sebelas Maret melakukan pengabdian masyarakat di Kelurahan Mangkubumen, Kecamatan Banjarsari, Kota Surakarta dalam rangka peningkatan kesadaran masyarakat dalam upaya mitigasi bencana gempa. Kegiatan pengabdian diawali dengan penggalian pengetahuan masyarakat tentang mitigasi bencana gempa, kemudian dilanjutkan dengan penyampaian informasi yang berkaitan dengan pengetahuan gempa dan dampaknya pada infrastruktur. Upaya-upaya mitigasi bencana gempa bumi, termasuk penerapan Standar Nasional Indonesia (SNI) gempa pada pembangunan infrastruktur juga disampaikan dalam kegiatan ini. Melalui kegiatan pengabdian ini diharapkan terjadi perbaikan pola pikir, pola tindak dan pola antisipasi serta aksi sigap dari masyarakat terhadap bahaya gempa bumi.

Keruntuhan geser sangat dihindari dalam merancang konstruksi bangunan karena karena sifatnya getas dan terjadi secara tiba – tiba sehingga sulit untuk diprediksi.

Penggunaan material alternatif pengganti semen sebagai penyusun beton semakin banyak ditemukan. Salah satunya adalah fly ash. Fly ash adalah sisa pembakaran batubara berupa partikel halus yang mengandung banyak silica (SiO2). Kandungan silica sangat cocok untuk reaksi kimia pembentukan beton. Pada penelitian ini, kadar kandungan semen akan diganti dengan fly ash sebanyak 50% pada pembuatan balok beton bertulang baja high volume fly ash self compacting concrete (HVFA-SCC) dan dibandingkan dengan beton normal. Balok uji berukuran 10 cm x 15 cm dengan panjang 150 cm. Pengujian yang dilakukan adalah uji kapasitas geser pada umur 28 hari dengan menggunakan alat uji loading frame dan memasang dial gauge di titik tengah bentang dan titik pembebanan pada 1/3 panjang balok. Hasil dari pengujian ini adalah nilai beban dan lendutan yang dapat diterima hingga mengalami keruntuhan geser. Berdasarkan penelitian ini, nilai kapasitas geser HVFA-SCC lebih besar dibandingkan beton normal, yaitu sebesar 32,125 kN untuk HVFA-SCC dan sebesar 20,500 kN untuk beton normal.

Fly ash merupakan limbah pembakaran batu bara berukuran mikron yang memiliki kandungan silika (SiO2) tinggi. Senyawa tersebut berfungsi sebagai pozolan untuk mengikat hasil sisa reaksi hidrasi berupa kristal Ca(OH)2menjadi CSH untuk meningkatkan kekuatan beton. Dengan kadar fly ash lebih besar sama dengan 50% dari total powder, serta penambahan super plasticizer agar beton mampu memadat sendiri, beton tersebut dapat disebut High Volume Fly Ash - Self Compacting Concrete (HVFA-SCC). Untuk melihat perilaku beton HVFA-SCC pada komponen struktur penelitian ini mengkaji perilaku lentur balok dengan penambahan 50% fly ash pada balok beton bertulang dan dibandingkan dengan lentur balok beton normal. Metode penelitian eksperimen menggunakan benda uji balok beton bertulang HVFA-SCC 50% dan balok beton normal dengan jumlah masing-masing 3 balok, dengan dimensi panjang 1500 mm, lebar 100 mm, dan tinggi 150 mm. Sampel balok dibatasi dengan penyeragaman mutu beton 30 Mpa. Pengujian dilakukan dengan metode four point loading pada jarak 1/3 bentang. Dari hasil penelitian didapatkan balok HVFA-SCC 50% mendapatkan nilai lendutan dan beban yang lebih besar dibandingkan balok beton normal. Dengan nilai indeks kekakuan sebesar 10,256 pada saat retak dan 4,072 pada saat leleh untuk balok HVFA-SCC 50% serta 7,831 saat retak dan 3,757 pada saat leleh untuk balok beton normal.

Fly ash merupakan limbah industri yang dihasilkan dari pembakaran batu bara. Terdiri dari partikel yang halus, dengan kandungan silica (SiO2) yang tinggi. Sehingga dapat dimanfaatkan sebagai bahan pozzolan sebagai pengganti semen yang merupakan bahan pengikat dalam pembuatan beton. Penggunaan fly ash dalam jumlah lebih besar dari 50% disebut dengan High Volume Fly Ash Concrete (HVFAC). Untuk mengatasi permasalahan pemadatan yang kurang optimal saat pengecoran, konsep HVFAC dipadukan dengan Self Compacting Concrete (SCC). Penelitian ini mengkaji pengaruh penggunaan kadar fly ash 50% dan 60% terhadap kuat tarik material beton. Dengan mengkaji beberapa parameter, yaitu hubungan load-displacement, energi fraktur elastik linear dan modulus elastisitas. Eksperimen dilakukan pada beton berdimensi 10x10x40 cm, dengan kadar fly ash 50% dan 60%. Diuji dengan beban tarik secara uniaxial. Rencana mutu beton 30 MPa. Karakteristik HVFA-SCC lalu dibandingkan dengan beton normal usia 28 hari. Dari hasil penelitian diperoleh kesimpulan, HVFA-SCC memiliki kekakuan lebih besar dari beton normal, dibuktikan dengan nilai modulus elastisitas yang lebih besar. Tepat sebelum beton putus, HVFA-SCC menghasilkan energi fraktur elastik linear yang lebih besar sehingga membentuk sinyal retak yang lebih baik sebelum terjadinya putus beton.

Unlike slender RC beams, shear failure mechanism of RC deep beams is mainly governed by shear compression; a considerable amount of the load is carried by the compression struts of concrete. For this reason, when subjected to a long-term sustained load, the shear strength of RC deep beam could be reduced as the sustained load might have negative impacts on the compressive strength of concrete. The purpose of this study is to investigate the influence of sustained loads on the shear capacity of RC deep beams. In this experiment, different loading rates were chosen as an alternative method to clarify the effect of sustained loads. Two main different types of loading rate, a normal loading rate of 10 mm/hr and a very slow loading rate of 0.01 mm/hr, were applied. 100x320x1200 mm RC beams with a ratio of shear span to the effective depth a/d=1 were tested under two-point loading. The test results showed that under very slow loading rate, the ultimate shear capacity was moderately reduced.

Residential buildings are included in the category of non-engineered buildings that suffered the most damage during an earthquake. This is because most of the building materials used and the working techniques, especially the reinforcement, do not meet the requirements. This research will be reviewed numerically using ATENA software on three types of numerical models, each of which represents non-engineered buildings, engineered buildings and reinforcement models with steel plates. The results showed that the non-engineered building model would experience the largest deflection and the smallest load bearing capacity, while the other 2 models experienced a smaller displacement with a greater load capacity. The best performance is shown in models with steel plate reinforcement, so that the reinforcement of steel plates in non-technical buildings will effectively increase the performance of non-engineered buildings.

Stirrups bars are widely used as shear reinforcement in reinforced concrete beams. It is quite attractive to explore the use of another type of material for stirrups. This study aims to investigate the shear behaviour of reinforced concrete beams using steel plate strips and conventional stirrups as shear reinforcement. Two full-scale reinforced concrete beams were tested to fail in shear in this experimental program, and the test parameter for this study was the types of shear reinforcement. The shear resisting behaviour of the beam specimens was discussed by evaluating the crack patterns, load-deflection response and the shear strengths of the beam specimens. The shear capacities determined experimentally were compared with the prediction values calculated based on the Modified Truss Theory. The ratio of the measured to estimated shear strength in the steel plate RC beams and reference beam showed a fairly good agreement as these ratios were only slightly different. Results of this study show that there is only a slight difference in the global behaviour of the steel plate RC beam and the reference beam using conventional stirrups.

Recently, fracture energy has received considerable attention owing to its importance in predicting crack propagation in concrete structures. The increase in the use of limestone aggregate concrete showing small fracture energy requires a deeper understanding of the key factors affecting fracture energy. In this study, a digital evaluation is performed for the fracture surface of concrete fabricated with different water–cement ratios, types of aggregate, and curing temperatures. The obtained results reveal the following relationships: (i) the ratio of un-broken coarse aggregate on the fracture surface decreases with weaker aggregate and stronger cement paste; (ii) the fracture surface roughness has a high correlation with the un-broken aggregate ratio under various conditions; and (iii) the variation in the fracture energy per unit compressive strength is uniformly explained using the area increment of the fracture surfaces.

High Volume Fly Ash – Self Compacting Concrete (HVFA-SCC) merupakan solusi untuk mengurangi penggunaan semen, dan tuntutan beton yang dapat mengalir tanpa menggunakan alat pemadatan. Penelitian ini dimaksudkan untuk menganalisis lentur pada balok beton bertulang High Volume Fly Ash – Self Compacting Concrete (HVFA-SCC) dengan 60% fly ash yang akan dibandingkan dengan balok beton bertulang beton normal yang diuji pada umur 28 hari. Benda uji yang digunakan adalah balok beton bertulang dengan luas penampang 10 cm x 18,5 cm dengan panjang 155 cm. Pengujian kapasitas lentur menggunakan loading frame dengan 2 titik pembebanan dengan jarak antar beban sebesar 45 cm. Dari pengujian ini didapatkan grafik hubungan beban-lendutan serta perhitungan kapasitas lentur balok beton HVFA-SCC 60%. Berdasarkan hasil penelitian ini kapasitas lentur pada pengujian balok beton bertulang HVFA-SCC 60% memiliki nilai yang lebih besar dibandingkan dengan kapasitas lentur hasil pengujian beton normal.

Sustained load problems, which can cause excessive deformation and severe damage to concrete structures, have been considered in current worldwide design codes by applying reduction factors on the compressive and tensile strength of concrete. A reduction factor in the shear design may also be required due to the decrease of shear-transfer action corresponding to the increases of the shear cracks opening. However, only a few studies are examining the effect of creep on shear performance of concrete structures, and the results are still inconclusive. As a complement to the previous experimental works, this study aims to investigate the effect of loading rate on the shear capacity of RC slender beams by non-linear finite element (FE) analysis. A spaceaveraged constitutive model with fixed multi-directional cracks was employed in the simulation of diagonal shear failure. The present study analytically examines the time-dependent effects on the beams under different loading rates until the delayed failure and compares the results with the previous experimental ones.

In order to achieve satisfactory global seismic behaviour of a concrete fame structure and to prevent undesirable local failures of its structural element, local strengthening of structural members by means of FRP wrap is one of the cost effective retrofitting strategy. This FRP wrapped column will increase the ductility of the element as well as the capacity that in turn will allow attaining more energy dissipating global performance. This on-going research aims to demonstrate the seismic performance of Low-to-Mid-Rise Concrete Frame retrofitted by FRP wrap in several configurations. The fragility curves of the structure before and after to local strengthening will be developed and analysed. Fragility curve will describe the probability of the structure that will exceed certain damage states given the ground shaking intensity during its service life. This curve allows evaluation for the retrofitting strategy is carried out rationally.