Earticle

The purpose of this study is to analyze the zero frequencies of the frequency response functions(FRFs). The peaks in FRFs represent the natural frequencies of the structure and the zeros provide additional information. The characteristics of peaks and zeros are defined and the calculation procedure to obtain the peaks and zeros from the relationship between frequency response function and stiffness and mass matrices are clearly explained. A system identification technique is presented using peak and zero frequencies and a damage detection example via a spring-mass system is provided.

moment by periods of reappearance, so evaluation indexes of both first seismic performance evaluation and second seismic performance evaluation, are found and the degree of earthquake-resistant of buildings is known. the periods of reappearance with 500 and 2500 year are used and MIDAS GENw is used to analysis the earthquake-resistant in the study.

Although connections of steel structure have been idealized as fully rigid joints or hinge joints for convenience in structural analysis and design process, many connections show the behavior of semi-rigid connections. The semi-rigid connections enable the construction process easy and make it possible to utilize the strength and stiffness of members. The large energy absorption capacity of the connections due to their inelastic behavior makes it possible to design member with good earthquake-resistant capacity. In this research, three-parameter model is evaluated as a simplified analytical model to describe the hysteretic behavior of connections of steel structure by utilizing the experimental results of partially restrained composite connections as well as composite beam. Three-parameter model which can simulate stiffness degradation, strength deterioration and pinching was successful to describe the hysteretic behavior of partially restrained composite connections as well as composite beam.

A computer based iterative algorithm for one-way GFRP concrete members is developed to the member thickness required to produce a computer deflection that satisfies maximum permissible deflections over a range of design conditions. The algorithm accounts for effects of cracking and long-term deflection due to creep and shrinkage. The calculated are compared with minimum thickness values based on ACI 318-05 allowable span-depth ratios based on the deterministic model. Recommendation are made for modify the current ACI 440.1R-01 provisions for minimum thickness.

construction for enlarging the interior space outward the existing buildings. These joints are constructed with post-installed dowel bars for shear connection. At the service load, the planar joint between existing and new slabs should behave in full composite mode, and any cracks shouldn't occur at the joints. In this paper, an experimental works were presented to evaluate the behaviors of planar joint between existing and new slabs for the serviceability and ultimate requirements. The main test variables were the number of post-installed dowel bars and the ratio of bending moment to shear force at the joints. The existing slabs were directly obtained from the apartment housing which will be demolished. From the test, the load-displacement curves at the loading point, and the shear displacement at the joint, the failure mode, the shear strength, and the strain of reinforcing bars were analyzed. Test results showed that the connection details had the sufficient strength at the ultimate states, as well as serviceability states.

This paper presents studies of the long-term behavior of the beams with recycled aggregate in transfer ratio under sustained loading. In this experimental program, three beams with replacement level(0%, recycled coarse aggregate 100%, recycled fine aggregate 50%) were tested in long-term bending to evaluate flexural strengthening effect of recycled aggregate and flexural performance when the sustained load removed. The beam were designed with net span of 2,000㎜ and rectangular cross-section of 170㎜ width and 170㎜ effective depth. Observation were recorded regularly for 380days on sustained multiple load. The experimental results showed that reinforced concrete beams with recycled aggregate(water absorption : 1.86～3.64%) were about similar long-term bending flexural mode with natural aggregate concrete beam. And concrete beams with recycled aggregate were higher than natural aggregate concrete beam.

This paper presents the evaluation of Pull-out strength of anchor that can cause a failure of the concrete on the basis of the design for anchorage. Test of Set Anchor and Set Strong Anchor, domestically manufactured and installed in plain concrete member are conducted to test the effects on embedment depth. Design of post-installed steel anchors termed the concrete Capacity Design (CCD) approach, is presented. This approach is compared the well-known provision ACI 318-05. The use of both methods to predict the concrete failure load of anchor in plain concrete under monotonic loading is compared. In this study, the concrete tension capacity of fastenings with Set Anchor and Set Strong Anchor in plain concrete predicted by ACI 318-05 and the CCD method was compared with the results of tests.

The purpose of this study is to investigate the functions and formations of the cell-units as aesthetic components in the spatial grid. The main subject covered here is the presentation of the morphological method of shaping spatial grid by application of cell-units satisfying the suitable form of polyhedra, tensegrity and hybrid structure. In accordance with the subject, the definition of the spatial grid and cell-unit, the relationship between them, and then the functions of the cell-unit are reviewed. And the formations of polyhedral units, tensegrity unist and hybrid units are generated by means of the modules of the simplest type or pattern. And also several basic ways in which one cell-unit can be joined to another and cell-units arranged are presented.

Generally, H-Piles are not used as structural members in the retaining wall system. But this is definitely a economic loss. So, CBS (Composite Basement Wall System) is developed in order to utilize H-Piles. The composite wall consists of steel beam and R/C wall. In this system, Shear connector as like a stud or a U-shaped reinforced bar should connect H-Piles to R/C walls. Stud connectors are used to combine those members. The flexural capacity of composite basement wall which consists of steel beam and R/C wall is evaluated by non-linear analysis in this study.

The objective of this research is to provide better knowledge on the behavior of strong axis SRC column - RC beam joint, supported by experimental results, that can be broadly applicable to many structures with similar characteristics. For this purpose, firstly literature reviews and field survey were made to classify the most commonly used for these types of joints. Then, experimental program was designed and performed including 6 SRC column - RC beam joint specimens designed with various joint details obtained from the literature reviews and field survey; ① RCW-P (passing through type), ② RCW-W (passing through and wing plate type), ③ RCW-F (passing through and field welding on the steel column type), ④ RCT-W (wing plate and passing through within the effective width of slab type), ⑤ HBR-L (long bracket type), and ⑥ HBR-S (short bracket type). Using the experimental results obtained from the quasi-static cyclic testing of 6 test specimens, structural performances of the joints such as hysteretic curve comparisons, maximum strength capacity, strength degradation beyond the maximum strength was reached, ductility comparisons, and energy dissipation capacity were investigated then following conclusions were made. Specimens with wide beam shape (RCW-P, RCW-W, RCW-F) and T beam shape (RCT-W) showed better structural performances than the bracket type specimens (HBR-L, HBR-S). These specimens also revealed to have higher strength capacities than the nominal design strength, consequently these types of joint details are recommended to be used in the field area. However, H beam bracket type specimens (HBR-L, HBR-S) need further study both analytical and experimental to verify the reason for unexpected structural performances.

f wy) as well as their interactive influence (pwfwy). Thus, it is reasonably expected that high-strength steel bars can greatly reduce the necessary amount of shear-reinforcing bars. On the other hand, although the bond strength is influenced by the amount of shear reinforcing bars, it is not affected by the yield strength. Thus, there is often an issue that bond failure occurs before shear failure depending on the arrangement of shear reinforcing bars. It is a common practice to set sub-ties for the transverse confinement of the main re-bars as a method to prevent the bond failure. However, it can also become a factor in decreased work efficiency due to the complexity of the construction. This study experimented with simultaneous use of high-strength transverse reinforcing bars (f wy=800㎫) and U-shaped transverse reinforcing bars of regular strength (f wy=300㎫) in an attempt to decrease the necessary quantity of shear reinforcing bars. The effect of this attempt was investigated through fundamental experimental research in terms of the improvement in shear resistance and bond strength as well as the ease of construction.

In this study, 4 types of specimens different the way of shear transfer was tested. In this study, different four types of specimens for RC and SC wall-slab joint was tested. To investigate the joint performance of the specimens, distribution of shear force and fixidity between wall and slab was surveyed by monotonic loading. We selected 3 types of transfer mechanism of shear force to the wall-slab joint ; 1. The shear force resister by the friction on the joint surface, 2. The shared shear force by the shear plate, 3. The shared shear force by studs on the joint surface. and evaluate the degree of contribution of each part in shear transfer. Especially, slippage of the top rebar was investigated to evaluate the fixidity of the wall-slab joint.

specimens for RC and SC wall-slab joint was tested. To investigate the joint performance of the specimens, distribution of shear force and fixidity between wall and slab was surveyed by monotonic loading. We selected 3 types of transfer mechanism of shear force to the wall-slab joint ; 1. The shear force resister by the friction on the joint surface, 2. The shared shear force by the shear plate, 3. The shared shear force by studs on the joint surface. and evaluate the degree of contribution of each part in shear transfer. Especially, slippage of the top rebar was investigated to evaluate the fixidity of the wall-slab joint.

The requirement for repair/retrofit has been increasing due to the problem of material and construction, design error and deterioration strength as time goes. For these reason, the research is to study shear strength and failure shape of beam retrofitted with CFS and CFP, in order to investigate the retrofit effect. Experimental work is performance for T shape beam with parameters, such as retrofit area dan type. Test result shows that the strength of specimen with CFP is higher than that of specimen with CFS. Also, the strength increased when the magnitude of retrofit increases.

Necessity of research about reinforcement details for performance improvement of shearing wall was required along with skyscraperlization of building. Therefore, studied about crack control method of shear walls with opening. Manufactured structure that apply existent reinforcement details and apply developed reinforcement details are structural experimented. As this experiment, could know that apply developed reinforcement details is effective crack control and energy dissipation ability. Angled type is effective in early elastic behavior. But it showed that ductility ability decreased in plasticity zone. Therefore make up for development details and experimental verification are judged that need.

The PCS system, which consists of precast concrete column and steel beam, is a kind of composite structural systems. In this paper, experimental study and Nonlinear finite element analysis is conducted to predict the structural behavior of precast concrete column and steel beam connected by using bolted connections. Based on experimental results from the seismic testing of eight interior PCS specimens, it shows that the PCS system is satisfied with seismic performance criteria of ACI such as strength deterioration, stiffness degradation and energy dissipation capacity except initial stiffness. In order to investigate cause of initial stiffness loss, we experiment one specimen applied symmetry monotonic loading and perform 3-D finite element analysis using the nonlinear FE program, ABAQUS. Analysis is stiffer than testing result, but we estimate testing results using the GAP element.

Recently, the function which in reinforced concrete structure comes to be demanded becomes diversification to follow and the High-Fluidity Concrete is demanded, also the research is actively advanced. From test of this research, the study of High-fluidity concrete using the fly-ash is necessary. Because of the result, it will be able to interpret the relationship with of replacement ratio of the FA and compressive strength with Exponential function. When it will be caused by with this function and the fly-as replacement ratio is same, it is judged with the fact that it will be able to forecast the compressive strength which it follows in the W/B which is various. Constructing the fundamental data which is necessary to a High-Fluidity Concrete mixture plan in objective, It adds the High-Range Water Reducing Agent and uses the fly-as the High-Fluidity Mortar which it manufactures, it fixed quantity analyzed the Rheology and the quality of the strength. The fly-as with the water relationship does a ball bearing action without, liquidity improvement but, when the fly-as of vast quantity is replaced, it delays a hydration reaction and the possibility the fact that the strength decreases it was.

Recently, The strenuous industrial waste is scattered and one of the oyster also make the serious environmental contamination. So, the purpose of this study is investigating an utilization ability as calcium binder of the oyster which is an industrial by-product. This study grasp physical properties of the calcined oyster powder of the paste, and conduct the strength test and flow test. The compressive strength and flow of the paste in calcining condition increase. According to baking condition strength of 1000℃(120minutes) is higher than any other conditions. The oyster powder from above 900℃ seem possibility as binder and hereafter, It is thought that the continuous research will be necessary.

are discussed. By use of a survey, moreover, the data for the reasonable uses are prepared. Silica is used for tile cement, grouting, mortar to repair, high performance concrete, etc in construction fields. Though Silica is more expensive than general sand, it is often used in repairing construction because it is pure as well as homogeneous and a prompt action is necessary during the polymer cement mortar or high performance mortar for grouting construction. As there aren't enough data of silica which is used for the construction fields, it is impossible to prospect about the vision of silica. So it is necessary to take statistics on the silica for the construction fields. Though each company has produced some silica which is sorted by sizes of particle, the particle sizes are not unified. As a result, it is necessary to make the unified silica standards for reasonable uses.

The purpose of this study is to analyze the physical properties of the hardened lightweight cement using the polyethylene tube and to make the fundamental data regarding a new lightweight concrete development. The aerated concrete is displaying various effects such as lightweight, insulation, soundproof, fire resistance characteristic and it is coming to be widely applied the slab layer of apartment as an insulating material. Therefore, demonstrating similar property of former aerated concrete and improving the defects, developing new hardened cement is needed. In this study, we predict adopting possibility of hollow core polyethylene tube, as a material to make cement hardening containing a lot of void. So we changed the mixing ratio, a diameter and length of the polyethylene tube and improved the compressive strength and unit capacity weight of the lightweight cement hardening body. From the test results, we judge that the aerated concrete is a developmental possibility.

Compared with unmodified mortars, the polymer-modifier mortars have superior qualities of flexural strength, adhesion and durability, so its rage of uses and consumed quantity increase. There is a constructional method of using polymer-modified mortar as a preparation to fill out unevenness on the floor of food factory, kitchen, etc. This paper discusses the strengths and adhesion of polymer-modified mortars as surface preparation materials for floor topping with polymer. This paper discusses the strengths and adhesion of polymer-modified mortars as surface preparation materials for floor topping with polymer. The polymer-modified mortars for surface preparation of polymer mortar are prepared with polymer-cement ratios of 0, 5, and 10% and tasted fir strengths, adhesion in tension.

A variety of flaws has been caused by a engineering method and an inappropriate selection of materials of building in carrying out tile-construction, which has been indicated to controversial problem on quality management of the tile construction and made construction companies and tile enterprises have an argument on that. In line with this, it is urgent that we should take a fundamental measure to reduce the flaws of the cracks by thoroughly investigating the cause of them. Therefore in this study, we would like to demonstrate a preventive measure of damage to the surface of the tile by making a model of a toilet, measure and analyze the conditions related to the quality management after the tile construction of the toilet according to experimental factor and it's level.

big damage scale at fire. Hereupon got conclusion such as that durability inflects superior aerated concrete and develop sandwich panel principal parts style cast-in-place aerated concrete panel in this research 1) As inner filler for low-cost style sandwich panel, presentation is possibility of aerated concrete presentation using cement and foaming agent 2) Manufacture condition of aerated concrete for cast-in-place aerated concrete fire-resistant panel manufacture is more than smallest unit cement amount 400㎏/㎥, water w/c more than 45% and the glass fiber mixing rate more than 0.7% about unit cement amount deduction be. 3) Stud establishment space is 1.0m through panel application examination of developed aerated concrete, space of armature is 20㎝, 1th maximum placement height is 1.5m, jointing distribution time more than 9 hours.

Air sealing is one of the most significant energy efficiency improvements, since an energy crisis in 1970s. But, a new problem by injurious gas that is bad for health from architectural materials by not carrying out natural ventilation is rising. Thus, recently it is concerned about the application possibility of photocatalyst. The purpose of this study is to evaluate the photocatalyst's applicability as the environment-friendly building materials according to the intensity of ultraviolet ray and the fixing method of photocatalyst. As the results of this study, the inorganic photocatalyst type, one of the fixing methods of photocatalyst, is definitely superior to the other from the self-cleaning by ultraviolet ray point of view.

dditives. 3 kinds of expansive additives produced in our country and 0, 5, 10, 15, 20% of ratio of addition rate are selected for this experiment. According to experimental results, flow of cement mortar with expansive additives is nearly same with flow of plain mortar and compressive strength, tensile strength, bend strength of cement mortar with expansive additives at 28 days is higher than that of plain mortar.

concrete as recyclable cement puts to practical use constructing basic data for design of mix proportion used recyclable cement and solves strength fall problem using micron separator, and does general recyclable cement high quality. As a result of X-ray diffraction(XRD) of rater HR-C than NR-C is aware that it come out the micron-separating to decrease the SiO2 peak below 50%. And a construction field which apply for compressive strength's 24～28MPa HR-C in order to realize NR-C of 44% and 51%. Recycle concrete capacity through improved recycle cement of manufacturing technique by micron-separating's new distribution more better improvement. Therefore, in this study, it need to more various study a recycle cement of high quality for reasonable and utility recycling than disposal concrete.

off. This paper shows a pullout strength of screw bolt by thickness of C channel. Pullout strength must be sufficient to resist the allowable tension of the fastener used in a tension connection. It depends on the metal alloy being fastened, the allowable shear stress of the metal, the fastener size and number of threads per inch, the internal thread stripping area, and the length of fastener engagement. Accordingly, in this study, the pullout strength is increased for increasing thickness of C channel. The load deformation curve of all examination body is similar.

of the concrete volume, they have a tremendous effect on the properties of concrete. But in our country, it as been increasingly pointed out the shortage of good quality aggregates. Consumption of coarse aggregates are in its stableness by substituting the crushed stone. Meanwhile, many concrete production company had suffered from the shortage of river and silica sand. But it is necessary to find substituting aggregate because of the restriction of aggregate gathering in river and sea. The results of mortar flow test and concrete slump test, the mortar and concrete with silica sand and crushed sand are better fluidity than the ones of river sand. And the results of mortar test, compressive strength of mortar with crushed sand is higher than the one of river sand, silica sand. Also, the compressive strength of concrete with crushed sand is higher than the other. According to the use of silica sand have not a bad effect on concrete.

The light weight foamed concrete has many advantages. Because there are many pores in the matrix of concrete at the viewpoint of the insulation and fire resistance. Therefore it has been used in applications requiring insulation. The insulation property of light weight foamed concrete varies according to density. Also, density is varies according to hardened matrix and pore rate. The purpose of the experiment is to know the thermal properties of light weight foamed concrete according to the change of density and the shape of iron plate, when heating the light weight foamed concrete. The results of this experiment are as follows. The higher density of concrete, the lower temperature of that. This tendency is not same as that of ordinary light weight foamed concrete. It seems that temperature decrease of concrete can be affected by vapor phenomenon of inner water of concrete when concrete is heated. The specimen of density 0.9 is showed lowest temperature. Also, the perforated specimen was efficient in preventing temperature increase.

Recently, Apartment Reconstruction Projects are performing only with the basis of profitability without establishing either certain criteria or standard guideline. In addition, the profitability information contained in a disposal plan tends to be considered as a fixed value, and it is frequently changeable because reconstruction projects have such a long time to complete and many participants with respective interests. As mentioned above, the new approach needs to be developed which covers the limitation of the unvaried one. Consequently, this study focuses on the probability approach considering not only variances that affect the profit, but the relationship between profit and risk, and then is modeling. This study is anticipated to improve the reliability and accuracy of expected value as well as apply to the decision making criteria quantitively about potentially hidden risks in that projects.