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Rehabilitation of corroded buried galvanized steel structures, including corrugated metal culverts (CMCs) and pipes (CMPs), requires a deep understanding of the corrosion process and the corresponding deterioration. The current paper describes an accelerated laboratory corrosion test of corrugated galvanized steel coupons exposed to sequenced wetting/drying cycles ranging from 50 and up to 1600 cycles. The analysis demonstrates the influence of applying an increased number of wetting/drying cycles on the acceleration of the developed corrosion in the buried galvanized steel coupons. The study examines changes in the steel geometry represented by thickness loss and the accompanied deterioration of the mechanical properties such as tensile strength, hardness, and ductility over relatively short periods of time. It was observed that corrosion was insignificant as long as the zinc coating of the galvanized steel lasted. However, when the zinc was almost fully depleted, the bare steel was directly subjected to the surrounding corrosive environment, causing greater corrosion damage during subsequent wetting/drying cycles. Based on four standard mathematical models, the paper also presents approximate average corrosion predictions for bare steel in the galvanized coupons, to assess the impact of potential damage due to corrosion and determine essential rehabilitation measures. [ABSTRACT FROM AUTHOR]

Rehabilitation of corroded buried galvanized steel structures, including corrugated metal culverts (CMCs) and pipes (CMPs), requires a deep understanding of the corrosion process and the corresponding deterioration. The current paper describes an accelerated laboratory corrosion test of corrugated galvanized steel coupons exposed to sequenced wetting/drying cycles ranging from 50 and up to 1600 cycles. The analysis demonstrates the influence of applying an increased number of wetting/drying cycles on the acceleration of the developed corrosion in the buried galvanized steel coupons. The study examines changes in the steel geometry represented by thickness loss and the accompanied deterioration of the mechanical properties such as tensile strength, hardness, and ductility over relatively short periods of time. It was observed that corrosion was insignificant as long as the zinc coating of the galvanized steel lasted. However, when the zinc was almost fully depleted, the bare steel was directly subjected to the surrounding corrosive environment, causing greater corrosion damage during subsequent wetting/drying cycles. Based on four standard mathematical models, the paper also presents approximate average corrosion predictions for bare steel in the galvanized coupons, to assess the impact of potential damage due to corrosion and determine essential rehabilitation measures.

An alternative approach to replacing corrugated steel culverts is to insert a new pipe inside the existing culvert and grout the space between them, a process known as sliplining. Though sliplining is a preferred rehabilitation approach among departments of transportation, very little research has been done to investigate the capacity enhancement provided by sliplining and how the load is shared between components in a sliplined culvert (i.e., the existing pipe, the liner, the grout, and the surrounding soil). A series of experiments was conducted on a deteriorated corrugated steel culvert at two different burial depths (600 and 900 mm) under surface loading before and after the culvert was rehabilitated with a grouted high density polyethylene (HDPE) slipliner. The rehabilitated culvert was found to be considerably stiffer and the diameter changes under surface load were reduced by more than 90% compared with the unrehabilitated culvert suggesting that the negative arching between the pipe and the soil has increased. The strains in the existing pipe were also reduced by more than 70% with negligible strain being measured in the invert of the culvert where the corrosion was concentrated. The results also indicated that when a neat grout with a compressive strength of approximately 30 MPa is used (what could be considered to be high strength in comparison with low density grouts featuring entrained air), the existing pipe and the grout carry most of the load, and the liner's main role is to improve the hydraulic conductivity. Additionally, because of the increased stiffness of the rehabilitated pipe, the surrounding soil carries less of the surface load applied above the pipe. [ABSTRACT FROM AUTHOR]

An important consideration in managing a river basin is how to treat the many stream crossings within the basin. Historically, corrugated metal pipe (CMP) culverts have been commonly selected for stream crossings throughout the world. The associated reduction in cross-sectional flow area causes an increase in water velocity at the culvert, which may become a barrier to fish passage. In Canada, existing guidelines compare the swimming performance of fish that may use the culvert with the average velocity within the culvert at some design flow. It is known that a velocity distribution occurs within culverts, and it is hypothesized that fish may possess the ability to sense and locate preferential swimming paths within low-velocity zones in a culvert. To facilitate the design of culverts in a manner that may better consider fish swimming performance, this paper compares the results of empirical and numerical modelling of the velocity distribution within partially full CMP culverts at uniform depth. An additional simplified model to estimate the percentage of the cross-sectional area with a water velocity less than any reference velocity is presented. Finally, the concept of using two-dimensional velocity distributions in combination with fish preference data for water velocity and depth is presented. [ABSTRACT FROM AUTHOR]

Highlights: [•] Experiments on culverts were modelled using FE and design code approaches. [•] Commonly used linear elastic FE models did not capture critical behaviour. [•] Design software predicted forces in intact but not deteriorated culverts. [•] FE models were used to predict linear elastic behaviour or provide an upper bound. [•] Design code equations underestimated thrust forces in most cases. [ABSTRACT FROM AUTHOR]

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This article presents the results of an analytical study on the structural behaviour of buried concrete-lined corrugated steel pipe (CLCSP). CLCSP combines the hydraulic characteristics of concrete pipe with an extended service life compared to unlined corrugated pipe. It is typically factory manufactured and shipped to the jobsite for roadway drainage applications. However, recent investigations have also demonstrated the ability to rehabilitate deteriorating metal culverts using a spray-on mortar lining approach. Since the primary intent of the concrete liner of manufactured CLCSP is to prevent abrasion and corrosion and improve the hydraulic performance, design guides for metal culverts lined with concrete have not been developed. A better understanding of the structural significance and the effect of the concrete lining on the strength of CLCSP is therefore needed. This study evaluated the structural effects of the concrete lining in CLCSP using finite element analysis and detailed soil modelling and proposes a design methodology for CLCSP. [ABSTRACT FROM PUBLISHER]

We conducted a series of volitional trials with wild-caught resident Coastal Cutthroat Trout Oncorhynchus clarkii clarkii in a 12.2-m-long, 1.8-m-diameter culvert test facility to develop a probabilistic model for predicting rates of upstream passage over a wide range of average velocities. The results of the passage trials indicated that the percentage of fish attempting passage and the percentage of fish successfully passing decreased as the trial target average velocity increased. At our highest trial average velocity of 2.4 m/s, 31% of test fish that chose to attempt passage passed after two nights of observation. Passage performance was generally better for larger fish, but this pattern was only statistically significant for a single trial (1.9 m/s). Fish ascended through the pipe more quickly as velocity increased. At higher test velocities fish favored the left side of the pipe (looking downstream), which contained a reduced-velocity zone created by the slightly oblique orientation of culvert corrugations. Our data provide the basis for a logistic model describing the probability of passage for Coastal Cutthroat Trout through bare corrugated metal culverts with no outlet drop. Empirical studies testing fish passage, such as this one, can inform culvert assessment protocols currently in use. [ABSTRACT FROM AUTHOR]

Load-rating factors are used to evaluate the service life or safety of culverts based on the culvert wall strength and soil cover depth over the culvert. Current culvert load-rating methods have deficiencies in identifying potential critical conditions of corrugated metal culverts. Current load-rating procedures do not provide explicit guidance to the engineer for load rating and evaluation of culvert condition. To ensure good performance over the design life, corrugated metal culverts must be designed and regularly evaluated using an effective load-rating method. The main objective of this study was to investigate the effectiveness of current load-rating procedures. Recommendations are made to improve the analysis and evaluation procedures for corrugated metal culverts. The proposed load-rating procedure is based on an extensive review of load-rating procedures and design practices, experimental data, and theoretical investigations. The proposed method does not include a rating factor for cover depth. However, the design cover depth is required to be checked during the initial design stage to ensure structural stability. New capacity reduction factors are introduced for culvert wall and seam, which require different appraisals for wall and seam during annual inspections. The effect of external live loads is not included in the proposed load-rating procedure for deep culverts and for culverts subjected to low live load stresses. Field data from 39 in-service culverts showed that the proposed load-rating procedure is effective in evaluation of the existing condition of culverts. [ABSTRACT FROM AUTHOR]

The paper presents the performance of four long-span deep-corrugated steel box culverts with spans of 8- and 14-m during backfilling, as well as comparisons with finite-element modeling and design codes. Two of the culverts were stiffened at the crown arch. The test results show that the stiffening applied on the culverts is quite effective. The crown rises of the respective stiffened culverts were found to be half those of the not-stiffened culverts. The influence of the structure geometry on the soil-passive earth pressure was confirmed, as well as the sensitivity of box culverts to soil loads with increasing spans. The results showed that the influence of the size and shape of the box culverts on the amount of thrusts must be better implemented in the design method. The finite-element analysis results were conservative when live loading was concerned but the crown displacements and thrust during backfilling were underestimated. [ABSTRACT FROM AUTHOR]

This paper presents the results of field performance tests of 39 in-service corrugated steel highway culverts in Ohio. The culverts had span lengths varying from 3.23 m(10.6 ft) to 7.04 m(23.1 ft) and backfill soil heights over the crown varying from 0.27 m(0.9 ft) to 7.47 m(24.5 ft). Static and dynamic load tests were conducted by driving heavy trucks across the culverts. Static loads were applied at ten different locations above each culvert. Dynamic load tests were conducted at six truck speeds varying from 8 km/h(5 mi/h) to 64 km/h(40 mi/h). A portable instrumentation frame was installed inside each test culvert to monitor deflections. Strains on the culvert walls were also measured at 14 locations using strain gauges. Effects of backfill height and loading conditions are investigated. According to the experimental results, a plot of maximum culvert deflection versus backfill height shows a nonlinear relationship. Maximum static load deflections were found to be consistently larger than the maximum dynamic deflections obtained using the same test truck. Deflections were nearly zero for deep culverts with backfill heights exceeding 4 m(13 ft). Maximum deflections correlate more closely to equivalent line loads than to total truck weight. The data also indicate that culvert behavior is more difficult to predict when backfill heights are shallow because other factors, such as culvert age and condition and soil type, likely play a significant role. [ABSTRACT FROM AUTHOR]

A large number of corrugated metal pipe-arch culverts are located under highways. This study investigates the field performance of four existing pipe-arch culverts under static and dynamic loads. Effects of various parameters were considered in selection of the culverts, including backfill height, loading conditions, age of placement, and culvert geometry. Static loads were applied at ten different locations above each culvert using heavily loaded test trucks. Six dynamic tests were conducted at speeds varying from 8 to 64 km/h. A portable instrumentation frame was installed inside each test culvert to monitor the deflections at five critical locations. During each test, strains were also measured using 14 strain gauges. Test results indicated that culvert response was influenced significantly by the backfill height. Nearly symmetrical deflection patterns were recorded for symmetrical loading about the longitudinal vertical plane through the crown. The maximum static deflections were larger than the maximum dynamic deflections for each culvert. [ABSTRACT FROM AUTHOR]

• High pH leachate from RCA road base can accelerate corrosion of underlying metal • Soil organic material promotes respiration of CO 2 that attenuates high pH • Column experiments conducted to investigate pH attenuation in underlying soils • Results indicate underlying soils attenuate RCA leachate pH to safe levels • RCA should be placed at least 0.3 m from metal to allow natural attenuation Recycled concrete aggregate (RCA) is widely used as a replacement for natural aggregates in road base construction worldwide. Still, there are concerns that the high pH of RCA leachate may cause accelerated corrosion of metallic-coated (aluminum or galvanized) steel culverts placed in the underlying soil. Carbonation from CO 2 produced in the soil by organic matter (OM) has been considered as a potential mechanism to attenuate RCA leachate pH to below aggressive conditions (pH < 9). Twelve field-scale columns of various lengths and containing compacted RCA underlain by sandy soil were constructed and observed over a 12-month period. Experimental variables included water infiltration rate, soil OM, and soil depth. CO 2 concentrations within the soil profile were measured throughout the duration of the experiment, and soil pH was measured at various depths at the end of testing. Only three of the experimental columns exhibited a soil pH greater than 9 (the pH level known to be detrimental to aluminized and galvanized metal) — two of these simulated limited depth (0.3 m) between the RCA base and culvert, and all three contained low OM soils (which is not expected to occur in practice, as soils under typical environmental conditions will typically be much deeper and contain more organic material). The results indicated that even when soil acidity was completely depleted, carbonation could sufficiently buffer soil pH from aggressively basic RCA leachate. Site-specific conditions, like soil OM content and depth to metallic infrastructure, should be considered when utilizing RCA as a base course. [ABSTRACT FROM AUTHOR]

The article offers information on the Mammoth Culverts, manufactured by Aveng Manufacturing Infraset, which have been used for the rehabilitation of a corrugated metal pipe which collapsed under André Greyvenstein Road near Gauteng's OR Tambo International Airport.

The article comments on a study which examines the effect of deterioration on the performance of corrugated steel culverts.

As part of an experimental program, a large number of in-service culverts were tested to investigate the influence of several parameters on field performance of culverts. These parameters included cover depth, load application, size, shape, and other properties of corrugated metal culverts. Response of 14 test culverts was simulated using a two-dimensional finite element program and a three-dimensional finite difference program. Deflections predicted from the two-dimensional analyses were larger than the deflections measured in the field. However, the experimental and calculated thrust forces were similar. Deflections and thrust forces predicted from the three-dimensional analysis were similar to the experimental results. The critical factors affecting the response of the culverts include cover depth, culvert size, metal thickness, and elastic modulus and other properties of backfill soil. The influence of these parameters on the culvert behavior is investigated through numerical simulations using the established modeling properties. [ABSTRACT FROM AUTHOR]