The behaviour of integral bridges undervertical and horizontal earthquake ground motion

Integral bridges are monolithic and are known to possess good earthquake resistance when founded on a stable soil. One important consideration is the relative displacements which can occur at the support points on structures where there is significant spacing between, i.e. bridges. Factors such as soil, foundation types etc. can all influence the dynamic response, and the stiffness of the bridge can influence how relative displacements affect the internal force actions within the structure. In this study, the effect of earthquakes on integral bridges built on several different soil types is examined, through computer simulation of an integral abutment bridge. The study is made based on Eurocode 8 recommendations, which provides data for different types of soil to be used for earthquake analysis. A symmetrical medium length integral bridge obtained from an existing structure is used for the analysis. Artificial EC8 spectrum compatible time histories (with a 0.35 g peak ground acceleration) are applied to the structure for a range of soil stiffnesses. In conjunction with this, both static and dynamic relative displacement studies are carried out to develop insight as to the significance or dominance of either dynamic or relative displacement effects. The final aim of this study is to propose a simplified approach for design/appraisal which can allow predictions of dynamic response based on the results of static relative displacement studies coupled with simple computer models, without having to resort to full nonlinear integration time-history analysis. Synthetic time histories for 5 different types of soil were created using Mathcad. The synthetic acceleration time history was validated using Seismospect (by Seismosoft). The time histories were then used to carry our full integration time history analyses in ANSYS (engineering simulation software) to simulate the dynamic response of the bridge. The results show that relative displacements play an important role in overall structural response of the integral bridge, compared to the pure dynamic response. The results also confirm that lower stiffness soils suffer a more detrimental effect of the earthquake compared to a soil of higher stiffness

ANALISIS RESPON STRUKTUR AKIBAT PENGARUH MULTI SUPPORT EXCITATION PADA JEMBATAN BENTANG PANJANG “STUDY KASUS JEMBATAN CABLE STAYED SURAMADU”

Analisis pengaruh gempa pada jembatan secara umum ada dua metode excitasi yaitu multi support excitation dan single support excitation. Multi support excitation adalah kondisi dimana perletakan jembatan mendapatkan percepatan yang tidak seragam akibat pembebanan gempa sedangkan single support excitation adalah kondisi struktur jembatan dianggap mengalami percepatan yang sama pada perletakannya. Metode multi support excitation ini biasa diperhitungkan dalam perencanaan dan analisa jembatan apabila bentang jembatan sangat panjang. Untuk jembatan bentang pendek dan sedang, biasanya kondisi ini diabaikan, padahal pada kenyataannya, kondisi ini dapat juga terjadi apabila tipe tanah yang ada pada perletakan jembatan sangat berbeda. Pada penelitian ini pengaruh multi support excitation dianalisis pada jembatan bentang panjang dengan tipe cable stayed dengan study kasus jembatan utama Suramadu. Jembatan Suramadu merupakan jembatan cable stayed yang memiliki panjang 818 m yang menempatkannya sebagai jembatang terpanjang di Indonesia saat ini. Menurut SNI jembatan Suramadu dikategorikan sebagai jembatan tipe rumit sehingga analisis riwayat waktu perlu dipertimbangan. Dikarenakan tidak adanya rekaman gempa pada lokasi jembatan sehingga dilakukan pembuatan accelegram time history dengan metode clough and penzien. Lokasi titik pengambilan data gempa yaitu Surabaya dngan jenis tanah keras dan Madura dengan jenis tanah lunak. Data accelegram time history kemudian dimasukkan kedalam software analisis struktur yaitu SAP 2000 V14. Hasil yang diperoleh menunjukkan bahwa dengan perencanaan multi support exciitation menghasilkan gaya-gaya dalam serta displacement yang lebih besar dibandingkan dengan metode single support excitation (percepatan terkecil) tetapi jika dibandingkan dengan percepatan terbesar maka SSE menghasilkan gaya-gaya dalam dan displacement yang lebih besar dari MSE. Untuk itu sebaiknya perencanaan gempa pada jembatan bentang panjang dilakukan dengan metode MSE karena lebih mereperesentasikan kondisi real dilapangan. Jika menggunakan SSE ambillah data SSE dengan percepatan terbesar. Kata Kunci : Gempa, Jembatan cable stayed, MSE, SSE

Behaviour of cable-stayed bridge’s girder to multi-support excitation

This paper describes the behaviour of the longitudinal and cross girder of cable-stayed bridge due to multi-support excitation. Cablestayed bridges should be analysed by different support accelerations since generally they have long spans. In this research, an 800 m long cablestayed bridge was assessed by giving different support accelerations. The method used is by arranging simulation using structural analysis software. The displacement time histories are obtained by converting the response spectra using MathCAD. The structural responses were then compared to the application of single support excitation. Results show that there is a significant discrepancy between the two analyses. Single support excitation causes lower responses if the ground motion magnitudes are similar to the small magnitude of the multi-support excitation, and it yields to a higher responses if the magnitudes are similar to the greater value of the multi-support excitation

Performance evaluation of high-rise apartment building using pushover analysis

Indonesia is a developing country that is experiencing rapid development growth. According to the Central Statistics Agency, in 2020 the population of Indonesia will be 270.20 million people. The increase in population from year-to-year results in increasingly narrow lands for development. Therefore, developers and businesspeople make the best use of this opportunity in the world of construction by carrying out developments, including high-rise apartments. As an earthquake-prone area, the planning process for buildings, especially tall buildings in Indonesia, must be carried out very carefully by considering the strength of the structure against high-intensity earthquake loads. Risk reduction strategies can be implemented through building vulnerability assessment by checking structural performance using pushover analysis. In this study, the performance of a 32-storey apartment building was examined using the pushover analysis method. The resulting calculation is that the performance of the structure is 0.0023 for the lateral direction and 0.0113 for the transverse direction. Through the ATC 40 method it is known that the result of structural performance is Damage Control, where after an earthquake the building is still habitable

Salford postgraduate annual research conference (SPARC) 2012 proceedings

These proceedings bring together a selection of papers from the 2012 Salford Postgraduate Annual Research Conference (SPARC). They reflect the breadth and diversity of research interests showcased at the conference, at which over 130 researchers from Salford, the North West and other UK universities presented their work. 21 papers are collated here from the humanities, arts, social sciences, health, engineering, environment and life sciences, built environment and business

Proceedings of the Salford Postgraduate Annual Research Conference (SPARC) 2011

These proceedings bring together a selection of papers from the 2011 Salford Postgraduate Annual Research Conference(SPARC). It includes papers from PhD students in the arts and social sciences, business, computing, science and engineering, education, environment, built environment and health sciences. Contributions from Salford researchers are published here alongside papers from students at the Universities of Anglia Ruskin, Birmingham City, Chester,De Montfort, Exeter, Leeds, Liverpool, Liverpool John Moores and Manchester

State of the art of seismic risk and loss assessment in structures

Earthquakes are known as one of the disasters that have fatal consequences for human safety. However, inevitably, the earthquake itself is not the leading cause of the losses suffered by humans, both material and soul. The most powerful thing in human safety is infrastructure such as buildings, bridges, and houses. Therefore, an in-depth analysis of the risk factors that the infrastructure will experience in a natural disaster is needed. There is a variable seismic hazard in the Southeast Asia region, ranging from high seismic hazard allied with the underneath of the Indonesian and Philippine archipelagos to moderate and low seismic tremors associated with a sizeable stable region on the Sunda Shelf. This paper describes the history of seismic risk and loss assessment of infrastructures. The method used is by doing literature reviews of the most recent research relating to seismic risk and assessment around the world. More than fifteen research results are studied and discussed to get a deep knowledge about seismic risk and the assessment of loss due to seismic disaster

PENILAIAN KERENTANAN SEISMIK PADA JEMBATAN PRESTRESS CONCRETE I (PCI) GIRDER TIGA BENTANG DI KURANJI - PADANG MELALUI PENGEMBANGAN KURVA FRAGILITAS ANALITIK

Jembatan memegang peran penting sebagai jaringan jalan penghubung untuk kegiatan tanggap darurat dan rute evakuasi pada saat maupun setelah gempa. Jembatan juga merupakan rute utama untuk mengangkut barang komoditas. Jembatan Multi Span PCI (PCI) yang terletak pada zona rawan gempa, Jalan Bypass, Desa Kuranji, Provinsi Sumatera Barat-Indonesia, adalah salah satu jembatan penting. Ini adalah rute utama dari Pelabuhan Teluk Bayur. Selain itu, jembatan ini direncanakan sebelum 2016 dimana beban gempa rencananya lebih kecil dari gempa rencana yang disyaratkan oleh peraturan terbaru. Oleh karena itu, untuk mengetahui tingkat kerusakan yang mungkin terjadi akibat gempa pada jembatan, perlu ada alat, yaitu kurva fragilitas yang dikembangkan dengan menggunakan fungsi distribusi lognormal berdasarkan respon struktural dari analisis pushover dan analisis dinamis nonlinier riwayat waktu. Hasil penelitian menunjukkan bahwa ketika spektrum respose target terjadi, kategori kerusakan jembatan berdasarkan pengelompokkan HAZUS adalah kategori Moderate. Kemudian, dari kurva fragilitas yang telah dikembangkan, probabilitas tingkat kerusakan terlampaui berdasarkan kategori HAZUS untuk kerusakan sligt, extensive, complete juga dapat diketahui. Kata Kunci : kurva fragilitas, gempa, pushover, riwayat waktu, jembata

A Simple Strengthening Method for Preventing Collapsed of Vulnerable Masonry Infills

A series of structural tests were conducted to examine the seismic performance of masonry infills strengthened with particular materials on infilled reinforced concrete (RC) frame structures. Six 1:4 scaled-down RC frame specimens had been prepared, including one brick-infilled frame without strengthening and five brick infills strengthened with innovative strengthening materials. The materials were steel wire mesh, chicken hexagonal wire mesh, plastic wire mesh, fiber-reinforced polymer (FRP), and plastic stretch film. The strengthening was diagonally applied on both surfaces of the masonry infill. The steel wire mesh, chicken hexagonal wire mesh, and plastic wire mesh were sewn using steel wire, while the FRP sheet was glued using epoxy resin and the plastic stretch film was glued using synthetic rubber adhesive. The specimens were tested following the FEMA 461 standard testing protocol, which involved applying lateral static cyclic loading to the specimens. The displacement transducer apparatus measured the deformations of the specimens, and crack propagation was observed during experimental works. The experimental results showed that most specimens exhibited an increase in their lateral strength, secant stiffness, deformation capacity, and energy dissipation. Among all prepared specimens, the specimen using plastic stretch film showed the best and most promising results, i.e., long deformation and steady lateral strength after yielding. This result suggests that using plastic stretch for strengthening can increase ductility performance. It is expected to withstand earthquake shaking, has low application costs, and is feasible for application even by unskilled local laborers