149 research outputs found
L-Shaped Steel Collars: An Alternative External Confining Retrofit for Improving Ductility and Strength of Rectangular Concrete Columns
Full text linkConfinement in concrete column has been well known to improve its strength and ductility. Such enhancement is primarily essential when needed to improve the behavior of concrete columns particularly in terms of ductility during the earthquake strike. This advantage is in line with the modern concept of moment-resisting frame which requires ductile structural framing members. Up to present, traditional transverse steel is still used as internal confinement in concrete column. Several researches have been conducted extensively to study the behavior of confined column, both analytically and experimentally. All these studies confirmed that internal confining method significantly improves the strength and ductility of the columns. However, sometimes the existing columns in a building do not satisfy the building code requirements either unintentionally or due to the unawareness of seismic hazards in terms of confinement. Once the column is built and cast, there is no way to revise the lack of transverse steel internally. The only way possible is to retrofit the columns by using external means. High demand of strengthening on existing RC buildings has made external confinement becoming increasingly popular as an alternative external confining retrofit for RC columns.
Various types of external confinement have been introduced to increase the strength and ductility of the columns, such as FRP wrap or even the use of steel jacketing. These external confining techniques have been proven to be successful in retrofitting circular concrete columns. Experimental programs as well as confining models for externally confined circular columns have been well developed. It is, however, still uneasy to provide an effective confining stress by external retrofit on square or rectangular concrete column. The non-uniform confining stress on column is due to high stress concentration at column corners. Only a few experimental and analytical studies addressed these issues.
The most recent proposed external confinement method is by using the steel collars with hollow square section. This kind of confinement method has been proven to work well as confining system for concrete columns. The strength and particularly the ductility of the columns have been improved significantly. However, it is still too heavy and uneconomical for use as column retrofit. The need of light and economic types of external confining retrofit is urgently required in the country like Indonesia. Thus, an external confining method that is utilizing light L-shape steel section is studied for its capability as an alternative retrofit for rectangular or square concrete columns.
This paper is a part of the first phase of a multiyear research project carried out by the authors. In this paper, a proposed alternative external retrofit for improving the ductility and strength of square concrete columns is presented. Eight columns specimens were cast and tested under monotonic compressive loading. A set of L-shaped steel collars have been introduced externally on square concrete columns prior to testing. The results have confirmed that the proposed external confining techniques considerably enhanced the compressive strength and ductility of the column specimens
A regional mapping procedure for finite element mesh design
No full textPractical algorithms for automated mesh design in finite element stress analysis are developed. A regional mixed mesh improvement procedure and a regional mapping procedure are considered. The error control, algorithm implementation, code development, and the solution accuracy are discussed. Numerical examples include automated mesh designs for plane elastic media with singularities. An extended application of the mapping procedure is to incorporate the mesh design with an explicit time integration method for a moving mesh region to handle stress and strain discontinuities at the wave front due to impact loadings. Examples for an elastic wave propagating through plane media are presented
Models of furniture design using coconut wood based on local culture for global and domestic markets
Full text linkThis study provides, for creative industries, a convenient overview of
a process that is still rarely used. This study aims to provide a model
of furniture design and production that can compete with the
growth of furniture exports and market demand. Demand is
increasing for furniture that is not mass-produced and is based on
local culture. The design thinking approach was used to produce
this model. This process consists of several steps, such as the study
of references, group discussions with expert participants and the
exploration and development of design products by students; the
products are based on local culture with coconut wood as the main
material. This research improves upon previous models. Building a
knowledge base in the initial phase was very important and
involved the identification and extraction of local resources. This
phase needs to be supported by experiential activities of ‘digging’
to extract design boundaries, along with other activities involving
the transformation of ideas into visual schemes as sources of design
inspiration. This phase is then followed by interpretation and
execution, including feasibility tests of the design product
Design thinking as a medium of professionalism and learning: A case of business incubator
No full textThis article is a case study that explores the understanding of design thinking strategies undertaken by final year students in the field of design and architecture in Business Incubator (BI) projects. The BI project is developed by the university with its partners or by students themselves with the determination that the project still provides a potential effect on BI. Many previous studies have been developed with reference to how Business Incubators (BIs) benefit students and contribute successfully to a developing country. The present study aims at investigating the university students’ perspective as BI’s executors who are required to remain professional while maintaining the importance of BI implementation in their university. Additionally, the uniqueness of the present study is that the design thinking approach used in the project provides also scientific enrichment in design methods. Furthermore, such an approach is universal and flexible in helping students who are still studying but they are required to be professional in running the project. We can figure out the shift in the use of this design thinking method when it is run by new learners in a real project world, not in a simulation studio
Dynamic Characteristic Identification of Seismic-Excited Multi-Story Buildings through Response-Only Technique
Full text linkIdentifying dynamic characteristics of civil engineering structures is still a challenging task. It intends to assess behavior of the structures under time-dependent loads. This paper discusses a methodology suitable for identifying the characteristics of multi-story buildings using only their measured response under earthquake ground excitations. Appropriateness of technique used for structural identification was corroborated through coherence of the structure’s responses. The methodology was applied for identifying the characteristics of 14-story and 20-story office buildings located in a high seismic region. Responses of these two buildings recorded during three different seismic ground motions were investigated. The buildings’ response spectral densities and singular values were computed and utilized to identify their dynamic characteristics, viz. modal frequencies, damping factors, and mode types such as bending or torsion mode. Results of this study were validated through comparisons with the results reported using different structural identification techniques. It indicated that the methodology implemented in this study was capable of identifying the dynamic characteristics of multi-story buildings using responses under seismic ground motions
A REGIONAL REFINEMENT FOR FINITE ELEMENT MESH DESIGN USING COLLAPSIBLE ELEMENT
No full textA practical algorithm for automated mesh design in finite element analysis is developed. A regional mixed mesh improvement procedure is introduced. The error control%2C algorithm implementation%2C code development%2C and the solution accuracy are discussed. Numerical example includes automated mesh designs for plane elastic media with singularities. The efficiency of the procedure is demonstrated. Abstract in Bahasa Indonesia : regional+refinement%2C+mesh+generation%2C+isoparametric+element%2C+collapsible+elemen
A REGIONAL REFINEMENT FOR FINITE ELEMENT MESH DESIGN USING COLLAPSIBLE ELEMENT
No full textA practical algorithm for automated mesh design in finite element analysis is developed. A regional mixed mesh improvement procedure is introduced. The error control%2C algorithm implementation%2C code development%2C and the solution accuracy are discussed. Numerical example includes automated mesh designs for plane elastic media with singularities. The efficiency of the procedure is demonstrated. Abstract in Bahasa Indonesia : regional+refinement%2C+mesh+generation%2C+isoparametric+element%2C+collapsible+elemen
A REGIONAL REFINEMENT FOR FINITE ELEMENT MESH DESIGN USING COLLAPSIBLE ELEMENT
No full textA practical algorithm for automated mesh design in finite element analysis is developed. A regional mixed mesh improvement procedure is introduced. The error control%2C algorithm implementation%2C code development%2C and the solution accuracy are discussed. Numerical example includes automated mesh designs for plane elastic media with singularities. The efficiency of the procedure is demonstrated. Abstract in Bahasa Indonesia : regional+refinement%2C+mesh+generation%2C+isoparametric+element%2C+collapsible+elemen
A REGIONAL REFINEMENT FOR FINITE ELEMENT MESH DESIGN USING COLLAPSIBLE ELEMENT
Full text linkA practical algorithm for automated mesh design in finite element analysis is developed. A regional mixed mesh improvement procedure is introduced. The error control%2C algorithm implementation%2C code development%2C and the solution accuracy are discussed. Numerical example includes automated mesh designs for plane elastic media with singularities. The efficiency of the procedure is demonstrated. Abstract in Bahasa Indonesia : regional+refinement%2C+mesh+generation%2C+isoparametric+element%2C+collapsible+elemen
Analisis Pengaruh Beban Lalu Lintas Terhadap Tingkat Kerusakan Jalan Soenandar Priyo Sudarmo, Kecamatan Prambon, Kabupaten Sidoarjo
Full text linkSoenandar Priyo Sudarmo Road often experiences significant stress due to
high traffic volume and load, particularly from heavy vehicles used for various
industrial activities in Prambon District. Additionally, during the survey, various types
of damage were identified, such as pothole, alligator cracking, and raveling. Based on
this, the author conducted a study to analyze the impact of traffic load on the level of
damage to Soenandar Priyo Sudarmo Road. The primary data used included road
damage data, riding quality, and traffic counting, while the secondary data included
road geometric data and Average Daily Traffic. This study used the Indrasurya and
Dirgolaksono (1990) method to analyze road damage, as this method is an adaptation
of various previous road damage evaluation methods, taking into account road
conditions in Indonesia The effect of traffic load on road damage was analyzed using
exponential regression to identify the non-linear relationship between the independent
variable and the dependent variable. The analysis results showed that the types of road
damage found were quite diverse, including potholes, raveling, alligator cracking,
distortion, transverse and longitudinal cracks, rutting, patching, and edge
deterioration. Based on the analysis per segment, the average damage value per
segment ranged from 18.85% to 45.16%, with riding quality in the RQ 1 to RQ 3
categories. Regression showed that heavy vehicles, particularly ESAL 1.2–22 trailers,
had the most significant impact on road damage with an R² value of 0.905. This study
indicates that traffic load, particularly from heavy vehicles, significantly contributes
to road damage. Based on these results, recommended road maintenance is
categorized into light, moderate, and no maintenance, depending on the condition of
each segment
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