Civil Engineering Dimension (E-Journal)
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EVALUASI PENURUNAN TANAH LIAT DENGAN METODE SUB-LAYER
Get PDFConsolidation settlement is commonly computed using one-point method, where a clay deposit is assumed as one layer and the stress increase from foundation is taken at the middle of the layer. This method is not accurate for determining consolidation settlement of a thick clay deposit.
This paper presents sub-layer method to compute consolidation settlement, which assumes that a clay layer is composed of several thinner layers. The results of both methods were compared to the settlement observed from the three experiments using a model of square footing with dimension of 10 cm by 10 cm, which was laid on a layer of clay. The thickness of the clay layer were 24 cm, 39 cm, and 50 cm or 2.4 B, 3.9 B, 5 B, respectively, where B is the width of the foundation.
The result shows that the consolidation settlement calculated using sub-layer method is always greater than that computed using the one-point method and it has a better agreement to the settlement of the models. Minimum number of layers that gives sufficient accuracy of settlement is 10.
Abstract in Bahasa Indonesia :
Penurunan akibat konsolidasi pada umumnya dihitung dengan memakai metode one-point, dimana lapisan tanah liat dianggap satu lapisan, dan penambahan tegangan akibat beban dari pondasi hanya ditinjau pada tengah-tengah lapisan. Cara ini kurang teliti terutama untuk menghitung penurunan lapisan tanah liat yang tebal.
Makalah ini mengemukakan metode sub-layer untuk menghitung penurunan akibat konsolidasi. Metode ini mengasumsikan bahwa suatu lapisan tanah liat terdiri dari beberapa lapisan tipis (sub-layer) dan perhitungan penurunannya dilakukan pada setiap lapisan tersebut. Hasil perhitungan dari kedua metode dibandingkan dengan penurunan yang diperoleh dari tiga percobaan pada model pondasi dengan ukuran panjang 10 cm dan lebar 10 cm, yang diletakkan di atas lapisan tanah liat. Ketebalan lapisan tanah yang dipakai adalah 24 cm, 39 cm, dan 50 cm, atau masing masing sebesar 2.4 B, 3.9 B, dan 5 B, dimana B adalah lebar pondasi.
Hasil penelitian menunjukkan bahwa penurunan yang dihitung dengan metode sub-layer selalu lebih besar dari penurunan yang dihitung dengan metode one-point, dan lebih mendekati penurunan hasil percobaan. Jumlah layer minimal untuk mendapatkan penurunan yang cukup akurat adalah 10 lapisan
MARKETING EXPENDITURES IN THE INDONESIAN CONSTRUCTION INDUSTRY
Get PDFIn the 1960s, a “new” marketing concept known as "four Ps marketing mix" appeared and shifted the focus from the product to the customer. The objective of the new concept was not only profit, and the means of achieving the objective expanded to include the entire “marketing mix”: product, price, promotion, and place (channels and distribution). Expenditures of marketing in a company should be explored from these mixes, because each mix would have an impact on the total marketing expenditures. These four mixes are the main aspects of marketing and thus, should represent almost all expenditures in marketing in a company. From this research it is discovered that the responding contractors have only average efforts to improve or innovate their service, mostly using the latest construction methods and management approach. Correlated to their policy in the fourth mix (Place), they are still national oriented and not international oriented in marketing their services, this may lead to the big question of their survival; their motivation to innovate is only average while their target market is only national market. Their attitude to use more intensive “fees” policy rather than both product innovation and promotion is also interesting. Big percentage of the responding contractors assumes these “fees” are regular marketing practices. This attitude may better be stopped to make the construction industry practices healthier. Attitude to use more product innovation and true promotion approach in marketing in construction must be encouraged systematically in the future, to improve competitiveness in the long term
A CASE STUDY ON TOTAL BUILDING PERFORMANCE EVALUATION OF AN INTELLIGENT OFFICE BUILDING IN SINGAPORE
Get PDFThe importance of understanding the performance of a building in a holistic sense is undeniable. This paper presents a method of total building performance evaluation, which has been widely used in many developed countries including Singapore. An office building with apartment and commercial retails called “intelligent building” is selected for building diagnosis. The occupant surveys and physical walkthroughs are carried out as subjective evaluations, while some objective measurements of indoor air quality and visual quality are also introduced in this study. The results indicate that generally, the occupants are satisfied with the quality of the building despite some insignificant indoor air quality and visual symptoms due to low temperature and glare problem in the office
PENELITIAN AWAL PENENTUAN WAKTU PENYELESAIAN PROYEK DENGAN METODE PERT PROJECT EVALUATION AND REVIEW TECHNIQUE
Get PDFConstruction involves many activities. Every activity need a portion of time which is defined as
duration. Duration is a statistic probabilistic variable, which is expressed in a range of values. So the
total time required to complete a construction project is also expressed in a range of times, thus the use
of PERT to evaluate construction time is considered to be more realistic. An observation on a
construction of a warehouse in steel structure in Surabaya shows that this method gives a tendency of
good result.
Abstract in Bahasa Indonesia :
Pembangunan melibatkan banyak aktivitas. Tiap aktivitas memerlukan sejumlah waktu, yang
didefinisikan sebagai durasi. Durasi adalah sebuah besaran statistik probabilistik, yang dinyatakan
dalam satu interval nilai. Maka total waktu yang diperlukan untuk menyelesaikan pembangunan
juga dinyatakan dalam satu interval waktu, sehingga penetapan waktu penyelesaian proyek dengan
metode PERT dirasakan lebih realistis. Pengamatan atas pelaksanaan sebuah gudang yang terbuat
dari struktur baja, di Surabaya, menunjukkan bahwa metode ini memberikan kecenderungan hasil
yang baik
FACTORS INFLUENCING THE COMPRESSIVE STRENGTH OF FLY ASH-BASED GEOPOLYMER CONCRETE
Get PDFThis paper describes the effects of several factors on the properties of fly ash based geopolymer concrete, especially the compressive strength. The test variables included were the age of concrete, curing time, curing temperature, quantity of superplasticizer, the rest period prior to curing, and the water content of the mix.
The test results show that the compressive strength of geopolymer concrete does not vary with age, and curing the concrete specimens at higher temperature and longer curing period will result in higher compressive strength. Furthermore, the commercially available Naphthalene-based superplasticizer improves the workability of fresh geopolymer concrete. The start of curing of geopolymer concrete at elevated temperatures can be delayed at least up to 60 minutes without significant effect on the compressive strength. The test data also show that the water content in the concrete mix plays an important role
NUMERICAL MODELLING OF CHICKEN-FOOT FOUNDATION
Get PDFThis paper presents an analysis of the chicken-foot foundation using the finite element method. The foundation is considered as a reinforced concrete slab resting on a number of reinforced concrete pipes filled with and surrounded by in-situ soil. The soil and the pipes were modelled by isoparametric solid elements while the slab was modelled by isoparametric thick-plate elements. The study was intended to illustrate the basic mechanism of the chicken-foot foundation. Three cases have been considered for the parametric studies. The parameters investigated are thickness of slab, length of pipes and spacing between pipes. It is shown that such a foundation improves the behaviour of the raft foundation. It is also found that all the parameters used in the parametric studies influence the behaviour of the chicken-foot foundation
A RATIONAL BUCKLING MODEL FOR THROUGH GIRDERS
Get PDFBuckling of a through girder generally is predicted by the so called U-frame approach which treats the compressed top flanges as compression members restrained elastically by the web stiffness. This study used a line-type finite element analysis to examine buckling behaviour of through girders, both a single span girder and a continuous girder. The elastic buckling loads were plotted for a range of span to height ratio
DAYA DUKUNG ULTIMIT PONDASI DANGKAL DI ATAS TANAH PASIR YANG DIPERKUAT GEOGRID
Get PDFThis research was conducted to compare the ultimate bearing capacity of square footing and strip footing rested on geogrid-reinforced sand via model test in the laboratory. The parameters studied were the top layer depth of geogrid below the footing (u), vertical spacings of geogrid layers (z) and the depth of the deepest geogrid layer (d) below the footing. For both square and strip footing, the value of u/B = 0.25-0.5 (B = width of footing) can give benefit to the ultimate bearing capacity of sand up to 2.5-3.5 times greater than unreinforced sand. On the value of z/B = 0.5, on the square footing case, could increase the bearing capacity up to 3.5 times bigger than unreinforced sand, while on the strip footing, z/B = 0.25 increase the ultimate bearing capacity up to 2.5 times greater than unreinforced case. At the value of d/B = 1.5, both square and strip footing could give benefits which amplified the ultimate bearing capacity up to 5 times and 3 times bigger than unreinforced sand respectively.
Abstract in Bahasa Indonesia :
Penelitian ini dilakukan untuk membandingkan kapasitas daya dukung ultimit pondasi bujur sangkar dan pondasi lajur yang berada di atas tanah pasir yang diperkuat geogrid melalui uji model di laboratorium. Parameter yang diteliti meliputi efek letak lapisan geogrid teratas (u), efek spasi geogrid (z) dan efek letak lapisan terbawah (d) dari geogrid terhadap kenaikan daya dukung ultimit pondasi. Untuk model pondasi baik bujur sangkar maupun lajur, nilai u/B = 0.25-0.5 (B = lebar pondasi) mampu meningkatkan daya dukung ultimit hingga 2.5-3.5 kali daya dukung ultimit tanah pondasi tanpa perkuatan. Nilai z/B = 0.5 pada pondasi bujur sangkar memberikan kenaikan daya dukung hingga 3.5 kali lipat dan pondasi lajur, nilai z/B = 0.25 memberikan kenaikan daya dukung hingga 2.5 kali lipat. Nilai d/B = 1.5, pada pondasi bujur sangkar dan lajur mampu menaikkan daya dukung tanah pondasi hingga 5 kali lipat dan 3 kali lipat dibanding tanah tanpa perkuatan
PERHITUNGAN STRUKTUR BAJA DENGAN METODE LRFD DENGAN CONTOH BATANG TARIK DAN TEKAN
Get PDFAbstract in Bahasa Indonesia :
Untuk menyambut akan diberlakukannya peraturan baja yang baru, yang menggunakan cara perhitungan LRFD (Load Resistance Factor Design), dimuat beberapa contoh soal yang dibuat oleh Ir. Oentoeng
APPLICATION OF LINEAR PROGRAMMING FOR DORMITORY DEVELOPMENT PLAN AT PETRA CHRISTIAN UNIVERSITY
Get PDFDormitory is a very important facility which have to be provided by a university. A survey to Petra Christian University’s students has been conducted to understand the required facilities and their financial ability. Linear programming has been used to calculate number of rooms and area of each facility which could satisfy the constraints and to obtain optimum profit. Number of bedrooms, number of bathrooms, and area of each facility, such as: living room, dining room, common room, cafeteria, book shop, mini market, phone booths, sport facilities, and parking space are recommended. Since the investment is financially feasible, the dormitory could be built in the future