Structural performance of damaged rigid pipe rehabilitated by centrifugal spray on mortar liner

Zhao, Yahong; Ma, Baosong; Ariaratnam, Samuel T.; Zeng, Cong; Yan, Xuefeng; Fu-zhi, Wang; Wang, Tianyu; Zhu, Zihao; He, Chunliang; Shi, Guopeng; Mi, Rongxi

doi:10.1016/j.tust.2021.104117

Cited by 26 publications

(6 citation statements)

References 34 publications

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“…Within their research, Roghanian and Banthia [31] studied non-reinforced cement coating and obtained approximately comparable results under a similar load test. However, in most cases, the object of the research is conventionally manufactured in factory reinforced concrete pipes directly [32,33], or the joint work of the coating and the host pipe [7,34,35]. Within these researches, reinforced concrete pipes can normally withstand significantly higher loads than those obtained in our case, as far as the investigated coating element is not a pipe, but is sprayedinplace directly to the restored pipe, which may certainly affect its strength characteristics.…”

Section: Resultsmentioning

confidence: 81%

“…Among the variety of trenchless methods of water supply and drainage networks restoration, the following approaches can be pointed out: spray in place (SIP) is the application of spraying coatings on the inner surface. One of the possible options is a cement mortar liner or a cement coating sprayed on the surface of the inner walls of the existing pipe [7,8]; cured in place pipe (CIPP) rehabilitation of the pipelines through a flexible (thermosetting) liner, which is inserted into an existing pipe [9]; sliplining is the method of pipe reconstruction when a new pipe is inserted into a deteriorated host pipe [10,11]; modified sliplining is a method of rehabilitation of host pipe with a spiral wound [12]; lining with inserted flexible polymeric hose [13]. Each of the listed methods of restoration has certain specific features, which determine the scope of their application to restore water supply and drainage networks.…”

Section: Introductionmentioning

confidence: 99%

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The research of reinforced cement liner for reconstruction of water supply and sewer pipes

Makisha¹

2022

J Appl Eng Science

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The research is focused on the investigation of the features of mortar liner reinforced with composite mesh, which may be one of the possible options in case of one possible method of trenchless reconstruction of water and sewer pipes. The research had two goals: to study the strength under static loading of a mortar liner reinforced with a composite mesh frame and to define the maximum depth of underground location of a coating element, which is of significant importance if a host pipe cannot bear external loads any longer. Within the research, two specimens of coating with the length of 1000 mm and diameter of 800 mm were tested. The compression results showed that for both specimens the loss of bearing capacity occurred to the fluidity of composite reinforcement under the load of approximately 30 kN. After the strength test, a calculation was made to evaluate the maximum depth of liner location in case if a host pipe fully exhaustits bearing capacity. The results of the calculation showed that the maximum height of the soil layer above the crown of a pipe is 2.8 to 3.2 m depending on the type and features of the soil.

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Section: Resultsmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

The research of reinforced cement liner for reconstruction of water supply and sewer pipes

Makisha¹

2022

J Appl Eng Science

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“…The segment concrete grade is C55, and the reinforcing bar is an HRB335 rib bar. Zhao found that after the interior of the concrete pipe is repaired by cement mortar, if the shear strength of the old and new interfaces is low, the old and new interfaces of the composite structure will strip under the external loads, which will affect the bearing ca- Zhao found that after the interior of the concrete pipe is repaired by cement mortar, if the shear strength of the old and new interfaces is low, the old and new interfaces of the composite structure will strip under the external loads, which will affect the bearing capacity of the structure [19]. Therefore, in order to improve the shear strength of the interface, when the segment is strengthened, the first step should be to plant reinforcement for the segment.…”

Section: Test Structurementioning

confidence: 99%

Experimental Investigations of a Tunnel Lining Segment Strengthened by In Situ Spraying Mortar

Wang

Zeng

et al. 2022

Applied Sciences

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After long-term operation, tunnel lining segments encounter various problems. Aiming at these problems, in this paper, we present a method of strengthening tunnel lining segments by in situ spraying mortar. An experimental study of the in situ spraying mortar was carried out to determine the compressive strength, flexural strength and interface properties (splitting tensile strength and shear strength) between concrete and H-70 mortar. The experimental results show that the mechanical properties of H-70 mortar are less dependent on the curing humidity than ordinary concrete under standard curing conditions, the 7-day compressive strength of H-70 is 55 MPa, which is 61% of the 28-day compressive strength. This shows that H-70 has high early strength and is very suitable for rapid reinforcement. The interface roughness has a significant effect on the splitting tensile strength, and it can be increased by chiseling to improve the bearing capacity of the strengthened structure. A full-scale loading experiment was carried out on the segment strengthened by in situ spraying mortar. The loading process, failure mode and ultimate bearing capacity of the strengthened structure were analyzed by full-scale loading experiment. The research shows that the ultimate bearing capacity of the tunnel segment strengthened by in situ spraying mortar increased significantly. The ultimate bearing capacity of the strengthened structure is 10% higher than that of the unstrengthened structure. The advantages and disadvantages of in the situ spraying-mortar strengthening method are analyzed in comparison with the internal-tension steel-ring strengthening method.

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“…On the other hand, a replacement brings in a new main pipe and starts a new life cycle. Suppose the cost of a maintenance is C m and the cost of a replacement is C r ; then, it is reasonable to assume C r > C m , especially when the no-dig technology is employed [45][46][47][48][49]. In addition to C m and C r , failure consequence is another primary source of costs.…”

Section: Definition Of Life Cycle Costmentioning

confidence: 99%

An Optimal Maintenance and Replacement Strategy for Deteriorating Water Mains

Lin

Chen

et al. 2022

Water

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Municipal water mains are built with a target service age of several decades. In such a long life, breaks can occur, even multiple times. Water mains can be maintained before or right at breaks. The former is referred to as the preventive strategy, whereas the latter is the corrective strategy. Depending on the costs of repair, replacement, and failure consequence, different strategies should typically be implemented in order to achieve the optimal watermain management in terms of life cycle costs. This study aims to investigate the optimal scenarios for the two strategies based on a two-time-scale (TTS) point process used to model the deterioration of water mains. The corrective strategy is to determine the optimal number n, where upon the n-th break, implementing a replacement for water main is justified, compared to a minimal repair. The preventive strategy is to determine the optimal replacement time in terms of pipe survival probability Ps. Monte Carlo simulations are used to investigate the optimal n and Ps considering a number of influential factors, including model parameters of the intensity function and ratios of maintenance, replacement, and consequence costs. Then, the full distributions of the life cycle costs are characterized with the mean of total life cycle costs being the target for optimization. Last, a case study is illustrated to demonstrate the application of both strategies in real water systems. An important finding is that with a typical pipe diameter of 400 mm and length of 200 m, the optimal n is typically less than five, and the optimal Ps is below 50%.

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Structural performance of damaged rigid pipe rehabilitated by centrifugal spray on mortar liner

Cited by 26 publications

References 34 publications

The research of reinforced cement liner for reconstruction of water supply and sewer pipes

The research of reinforced cement liner for reconstruction of water supply and sewer pipes

Experimental Investigations of a Tunnel Lining Segment Strengthened by In Situ Spraying Mortar

An Optimal Maintenance and Replacement Strategy for Deteriorating Water Mains

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