• 대한기계학회논문집
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• 제17권9호
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• pp.2271-2279
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• 1993

In the case of life prediction on the structures and machines after long service, it is natural to consider a degradation problems. Most of degradation data form practical structures are isolated data obtained at the time of periodical inspection or repair. From such data, it may be difficult to obtain the degradation curve available and necessary for life prediction. In this paper, for the purpose of obtaining a degradation curves, developed the simulate degradation method and fatigue test and Charpy impact test were conducted on the degraded, simulate degraded and recovered materials. Fatigue life prediction were conducted by using the relationship between fracture transition temperature (DBTT : vTrs) obtained from the Charpy impact test through the degradation process and fatigue crack growth constants of m and C obtained from the fatigue test.

• Smart Structures and Systems
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• 제4권5호
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• pp.517-530
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• 2008

This paper deals with civil infrastructures in general, sensor and smart structure technology, and smart steel structures in particular. Smart structures technology, an integrated engineering field comprising sensor technology, structural control, smart materials and structural health monitoring, could dramatically transform and revolutionize the design, construction and maintenance of civil engineering structures. The central core of this technology is sensor and sensor networks that provide the essential data input in real time for condition assessment and decision making. Sensors and robust monitoring algorithms that can reliably detect the occurrence, location, and severity of damages such as crack and corrosion in steel structures will lead to increased levels of safety for civil infrastructure, and may significantly cut maintenance or repair cost through early detection. The emphasis of this paper is on sensor technology with a potential use in steel structures.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2001년도 학술논문발표회
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• pp.136-141
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• 2001

If we build new building after demolition of commercial building that is located in the downtown, it will be caused a social and environmental problem as wasting of resources and generating of waste. In this study, I investigated about remodel ins, this conclusion is given below. 1. Reconstruction cost is 2.1 times, and construction period is 1.4 times as much remodeling. So remodeling has an advantage. 2. For repairing and reinforcing timeworn building, we reinforced it as using carbon fiber sheet (girder, slab) and injecting method steel plate bonding Also, we tried to maintain efficiency of new building as using epoxy to protect concrete crack. 3. In the side of waste products and cost, remodeling has much more advantage than reconstruct. But demolition used construction period much. Because it had to be reused as repairing and reinforcing. And there was no difference between remodeling cost and reconstruct cost. If we develop research with enterprise.university.laboratory to exploit material and equipment and to train specialized engineer who will has a capacity to know construct repair and reinforce, it can be attribute to prevail remodeling in new construct market.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.493-498
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• 1999

Many concrete pavements closed to the end of service life in out country need to repair. We investigated material and mix designs for thin bonded concrete overlay and applied it to concrete pavement rehabilitation. The concrete with Type III cement showed earlier strength and better durability than the concrete with Type I cement. Designed concrete mixture with TypeIII cement made it possible to open the road earlier against heavy vehicles, increased traffic despite of cold weather in winter. In the field examination after four month, there was no defects like as shrinkage crack, spalling, surface abrasion and scaling, and good traffic condition has been maintained.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.485-490
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• 2000

Because of occuring easily the crack, debond, lutting on asphalts pavement of bredge decks under traffic's heavy weigt load. We investigated the application of latex modified concrete to resurface and repaire bridge decks for preventing the above problems. Here, Using the ordinary portland cement and high early cement, We rested mix design, workability, compressive strength, adhesive power, drying shrinkage, carbonation, and economic estimation etc. We selected the condition of application to resurface and repaire bridge decks and detected high early cement is superior to ordinary portland cement in results of analyzing the application of the repairing bridge decks and economic estimations.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.367-370
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• 2003

This study was carried out to suggest the effective reinforcing method which can evaluate the tensile capacity of cast-in-place anchor with cracks. Currently, cast-in-place anchor is used widely for the fastening of equipment in Korean NPPs. 26 test specimens with a single anchor under 4 cracked conditions are prepared using plain concrete. The distance between crack and anchor and reinforcing materials were selected as the main test variable. The tensile force was applied using a actuator with a capacity of 100 tonf using a displacement control method of 0.5 mm/min velocity. Test results from this result show the combination of carbon plate and epoxy will be more available for repair and reinforcement of equipment foundation system in NPPs. Further experimental work is indeed involving the epoxy injection effect and adjustment of reinforcing location of carbon sheet.

• 한국농촌건축학회논문집
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• 제15권1호
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• pp.29-36
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• 2013

This study is to diagnose causes of damage and defects on external walls of brick structures, focused on "Naju Noahn" Catholic Church of Modern Architectural Properties. The causes of crack and deflection are overloading, shortage strength of arch. Among those, main cause is cauesd by shortage strength of arch because center of arch is dislocated and skew back of arch is small angle. The causes of damage and elimination are weathering, plants of friction, freezing and thawing, durability decrement of material and attach defection. This defects and damage is caused by high-moisture that occurs in soil. The causes of discoloration are change of soil moisture and flimsy brickwork. These defects and damage are mainly occurred in coping of cornice, weathering of window sill.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.161-166
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• 2003

The purpose Performance degradation of concrete structures is generally caused by the deteriorations, such as surface collapse, pop-out, crack, and so on. It may result in serious defects of the concrete structures. Thus it is very important to detect and repair the defects of concrete structures within a proper time to assure the structural safety. However, the defects due to the deteriorations are usually difficult to find by visual inspection. A sensor is developed in this study, which may give early indications for degradation of concrete structures and show the locations of the demage. Cracks can be defected by the liquid in a small glass capsules which are embedded in the concrete structures. This paper discusses the applicability of that was developed smart concrete.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.450-455
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• 1997

In recent years the research and development about the new material proceeds rapidly and actively in building industry. We are concerned with high-strength concrete as a new material. As the building structure becomes bigger, higher and more specialized, so does the demand of material and member with high strength for building expands greatly. In the future, we will quite need to research repair and rehabilitation to make high strength concrete structural building for our safe. So, I did an study on carbon fiber sheet rehabilitation(CFSR) of reinforced high strength concrete beams. The carbon fiber reinforced plastic(CFRP) bonding method is widely used for reinforcing the existing concrete structure among the various methods. The test results indicate that CFS is very effective for strengthening the damaged beams and controlling deflections of the repaired beams. When carbon fiber sheet rehabilitation of reinforced high strength concrete beams happened diagonal crack, the increase in the number of CFS layer didn't effect the increase in strength of beams. Also, by changing the CFS stick position gave diversified ultimate load in CFSR beams.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.475-480
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• 2003

Latex modification of concrete provides the material with higher flexural strength. This increase in flexural strength can attribute to the crack-arresting action of polymer in concrete, and also to the bonding they provide between the matrix and aggregates. This experimental study presents the fracture behavior of 12 flexural reinforced concrete beams repaired or strengthened by latex-modified concrete with the main experimental variables such as overlay thickness, strength thickness, and shear reinforcement. The results are as follow: All beam specimens having shear reinforcement were failed by delamination rupture at concrete interface at about 80% of ultimate loading after flexural cracking. All specimens overlayed and strengthened by latex-modified concrete (LMC) showed higher ultimate flexural strength than OPC control specimen, but lower than LMC control specimen. This increase in flexural strength could attribute to the high bonding they provide between the matrix and aggregates. All specimens except two shear unreinforced showed quite similar and consistent displacement behavior. The effect of overlay and strength thickness on the load-displacement relationship were a small at this study.