Japan Society Of Civil Engineers Research Articles

Engineering characteristics and classification based on JSCE in portal zones of Tunnel A, Yogyakarta - Bawen toll road, Magelang District, Central Java Province

The Yogyakarta - Bawen Twin Tunnels emerge as an environmentally conscious solution for Toll Road Phase 5 (STA 6+300 to STA 27+640), addressing the ecological impact of open-cut excavation, which demands a staggering 1,209,056 m3. Open-cut excavation not only incurs substantial operational costs, encompassing disposal and treatment, but also poses threats like groundwater loss and erosion-induced landslides. The twin tunnels mitigate these concerns by limiting excavation volume to a mere 1/8, averting substantial costs and ecological damage. Challenges persist, particularly in the portal zones of Tunnel A, characterized by a shallow overburden and exposure to weathering. The Japan Society of Civil Engineers (JSCE) Method proves instrumental in assessing ground quality in these zones, considering factors such as competence, unit weight, unconfined compressive strength, depth of cover, elastic wave velocity, boring core condition, and geological characteristics. The analysis reveals a ground quality classification of E for the portal zone in Tunnel A, emphasizing the necessity for a meticulous design approach that incorporates analytical methodologies alongside empirical considerations. Notably, the unconfined compressive strength ranges from 32.89 to 472.88 kPa, and the elastic wave velocity spans 402 to 2000 meters/sec, reinforcing the imperative for a comprehensive and analytically informed design for excavation and support systems.

Recommendation of excavation method and support system based on engineering geology at Riam Kiwa Dam diversion tunnel, South Kalimantan, Indonesia

River flow diversion is one of the most critical factors that must be considered for the success of dam construction. Soil and rock can support and load; therefore, understanding their strength and properties before tunnel construction is essential. Tunnel excavation and support depend totally on rock mass quality. Surface geological mapping, drill core analysis, and laboratory testing characterized the engineering geology conditions. Rock Mass Rating (RMR) and Japan Society of Civil Engineers (JSCE) methods were compared to determine rock mass quality and recommend excavation and support systems. Results showed that slightly weathered andesite lava and tuff lapilli lithologies dominate the tunnel alignment. Based on RMR, the rock masses quality along the tunnel alignment consists of poor and fair, and based on JSCE, the tunnel alignment consists of D I and C II rock categories with L and M massive rock types. Top heading and bench are recommended for tunnel excavation based on RMR, and the double bench and full-face method with an auxiliary bench cut are recommended for tunnel excavation based on JSCE. Although the characteristics of other support systems vary marginally, support systems based on RMR and JSCE recommend rock bolts and shotcrete as the primary tunnel support systems.

An empirical assessment of selection excavation methods and support system in Budong-Budong Dam diversion tunnel, Central Mamuju, West Sulawesi Province

Budong-Budong Dam is located on Salulebo River, West Sulawesi Province, and has a diversion tunnel to divert river flow so as not to interfere with construction at the main dam. This diversion tunnel has a D shape which is dimensions 5 m. The Method used in empirically assessing rock mass quality is Rock Mass Rating (RMR) and Japan Society of Civil Engineers (JSCE). The data used are RMR values and rock-type categories. The results show that the diversion tunnel is in lithology tuffaceous sandstone intercalation tuffaceous siltstone and tuffaceous breccias. Weathering degree from slightly-weathered to highly-weathered. The dominance RMR value is 27-53 and rock-category is CII with L massif rock type. The excavation method based on RMR is top-heading and bench and the excavation method based on JSCE is a full-face method with an auxiliary bench cut. Support systems proposed by RMR and JSCE are rock-bolts, shotcrete, and steel sets (steel support). Even though it has been done empirically, it needs to be considered for modeling to be effective and efficient.

A Study on Earthquake Loading to Secure Safety During Railway Bridge Construction

Railway bridges are widely built based on the national railway network and maintenance plans. As in the case of an earthquake in Pohang, the seismic safety of constructions in Korea is very important in the prevention of disasters. Therefore, the cases of damage caused by earthquakes and additional horizontal forces during bridge superstructure constructions were investigated among domestic and foreign earthquakes, and the details of overseas related design standards were confirmed. The horizontal forces based on the domestic seismic design standard (KDS 24 17 10: 2016) on the PSC beam, PSC box, steel box, and wind load were compared with the design codes based on the Eurocode 8 (Part 2), Japan Railway Technical Research Institute (RTRI), Japan Society of Civil Engineers (JSCE), and East Japan Railway Company (JR East).

Flexural Analysis Combined with Freeze-thaw Depth for Reinforced Concrete Beams and Columns

This study presents a kinematic model for flexural analysis of RC beams and columns subjected to freeze-thaw action based on upper bound theorem. The developed model enables analytical derivation of the contribution of damaged concrete when actual deterioration profile is idealized as an assemblage of undamaged and damaged zones based on freeze-thaw depth obtained from concrete core specimens. The accuracy of the analysis is verified by comparing its predictions with available 21 RC columns and beams failing in flexure after freeze-thaw exposure. The predicted results show good agreement with the test results within error of 6% on average. Thereafter, the developed analysis predicts the ultimate moment capacity of a RC beam, which was taken from an existing bridge slab replaced because of the combined effect of frost damage and fatigue. Results demonstrate that the present analysis could support a rational decision-making regarding the need for repair or rehabilitation. This paper is the English translation from the authors’ previous work [Kanazawa, T., Nakamura, T., Sakaguchi, J. and Kawaguchi, K., (2021). “Flexural analysis combined with freeze–thaw depth for RC linear members.” Journal of Japan Society of Civil Engineers, Ser. E2 (Materials and Concrete Structures), 77(4), 177-186. (in Japanese)].

20<sup>th</sup> meeting on the use of wood for civil engineering by Japan Society of Civil Engineers

20<sup>th</sup> meeting on the use of wood for civil engineering by Japan Society of Civil Engineers

Punching Shear Capacity of Prestressed Concrete Slabs Made of Lightweight Concrete Mixed with Short Fibers

The purpose of this study is to examine means of creating light and very strong prestressed concrete slabs made of lightweight aggregate concrete mixed with short fibers. The experiments reported in this paper demonstrated that the ratio of short fibers in the mix must be kept to 0.5 vol% or less, in order to obtain the same strength as that demonstrated by lightweight aggregate concrete designed to a standard strength of 50 N/mm2. In addition, the results of load testing various slabs confirmed that lightweight PC slabs mixed with 0.5 vol% of short PVA fibers had the same punching shear capacity as PC slabs made from normal weight concrete. The results led to the conclusion that the increase in the shear capacity of lightweight PC slabs mixed with short fibers was caused by the suppression of the progress of cracks in the RC direction and an accompanying tide arch formation in the PC direction.This paper is the English translation of the authors’ previous work [Kitano, Y., Ito, H. and Suzuki, S., (2020). “Study on lightweight and high strength prestressed concrete slab by using lightweight concrete mixed with short fibers.” Journal of Japan Society of Civil Engineers, Ser. E2 (Materials and Concrete Structures), 76(3), 239-254. (in Japanese)].

Behavior of Alkali-Activated Fly Ash through Underwater Placement.

Underwater concrete is a cohesive self-consolidated concrete used for concreting underwater structures such as bridge piers. Conventional concrete used anti-washout admixture (AWA) to form a high-viscosity underwater concrete to minimise the dispersion of concrete material into the surrounding water. The reduction of quality for conventional concrete is mainly due to the washing out of cement and fine particles upon casting in the water. This research focused on the detailed investigations into the setting time, washout effect, compressive strength, and chemical composition analysis of alkali-activated fly ash (AAFA) paste through underwater placement in seawater and freshwater. Class C fly ash as source materials, sodium silicate, and sodium hydroxide solution as alkaline activator were used for this study. Specimens produced through underwater placement in seawater showed impressive performance with strength 71.10 MPa on 28 days. According to the Standard of the Japan Society of Civil Engineers (JSCE), the strength of specimens for underwater placement must not be lower than 80% of the specimen’s strength prepared in dry conditions. As result, the AAFA specimens only showed 12.11% reduction in strength compared to the specimen prepared in dry conditions, thus proving that AAFA paste has high potential to be applied in seawater and freshwater applications.

Rock mass classification for design of excavation method and support system of tunnel 1 Sigli-Aceh toll road, Indonesia

This paper presents an empirical design of the excavation method and the support system of tunnel 1 of the Sigli-Aceh toll road, Indonesia, based on the rock mass quality of Rock Mass Rating (RMR) and the Japan Society of Civil Engineers (JSCE). The results showed that the tunnel route consisted of fair to good quality calcarenite interlayered by sandstone and D II to C II rock categories based on the RMR and JSCE. Based on the RMR, recommended excavation method for the tunnel section having fair to good quality rock mass is the full-face, top heading and bench methods. The recommended support system is a rock bolt with a length of 3 - 4 m, spacing 1.5-2.5 m, shotcrete thickness 5 - 10 cm. Meanwhile, the recommended excavation method based on the JSCE classification with rock categories DII and CII is bench cut, and full-face methods with auxiliary bench cut. The recommended support system is a rock bolt with a length of 3 - 4 m, spacing 1.2 m, shotcrete thickness 10 - 20 cm, steel ribs H-125 -H-150, spacing 1-1.2 m, and lining 30 cm on the wall and 40 - 50 cm on the floor.

Mini Special Issue on Tsunami Numerical Modeling Benchmarks – Challenges of Tsunami Modeling Hackathon –

Numerical simulation and modeling became an essential technology in tsunami research and disaster management. Various numerical models were proposed and utilized for the development of tsunami risk assessment, inundation maps, and evacuation plans. The model verification and validation standards would be crucial to ensure sufficient reliability of tsunami risk assessment, inundation maps, as well as a consistency among various efforts. Common approach to ensure sufficient accuracy and reliability of numerical modeling is developing benchmark problems of hydraulic experiments and to use them for numerical model’s verification and validation. To satisfy this requirement, “Tsunami Modeling Hackathon” was held in September 2020 to organize new benchmark problems in numerical modeling of tsunamis and to improve their reliability and accuracy. Hackathon is an intensive-gathering event of computer programmers and others involved in software development to create outcomes by the end of the event. This event was organized by Prof. Tomoyuki Takahashi of Kansai University and his colleagues, who led the tsunami research subcommittee in Japan Society of Civil Engineers (JSCE). Tsunami modeling hackathon, in which about 23 teams and 162 researchers joined, included experiment and modeling teams in seven benchmark problems: urban tsunami inundation, landslide tsunami, tsunami loading on seawalls and coastal structures, sediment transport, drift of floating objects. The modeling groups performed the blind tests to cross-validate and interpret the results of their simulations in seven benchmark problems given by the experiment groups and discussed the improvement. This special issue reports the outcomes of the tsunami modeling hackathon, and includes six papers (five in this issue, one in the regular issue). We hope this issue will provide useful insights for tsunami modelers and contribute to establishing a standardized way to ensure that various tsunami numerical models would be validated through the benchmark problems.

Problems of Local Disaster Management Plan at the Great East Japan Earthquake and Achievements 10 Years Later

According to the survey of the Japan Society of Civil Engineers, sending and receiving of support, vertical division of organizations, business continuity, local collaboration, management of disaster prevention and mitigation, advance preparation for reconstruction, and number of personnel are listed as the problems of a local disaster management. As for these problems, the achievements are made clear by analyzing concretely the progress for 10 years after the Great East Japan Earthquake based on the data and examples. As a result it is found out that at the state level the know-how to formulate the subordinate plan of a regional disaster management plan has been summarized and the training system is being arranged to develop the human resources. And at the level of the local governments the rate of the local governments which have worked out a business continuity plan improves and the number of the personnel engaging in disaster management increases significantly. Furthermore, some remarkable advanced examples are observed in the problems of “vertical division of organizations” and “local collaboration.” In the future these measures should be implemented in the individual local governments and elaborated continuously by improving themselves through friendly rivalry.

Effect of mat anchorage on flexural bonding strength between concrete and sand coated GFRP bars

In the present study, the impacts of using six different configurations of handmade mat anchorages on the improvement of bonding between normal concrete and GFRP bars have been investigated. To do so, 63 beam specimens of three different concrete mixes were cast. The beams were cast in accordance with RILEM recommendations and all tests were conducted under the same condition. The results indicated that the use of anchorage system could substantially enhance the bond between concrete and GFRP bars. However, the increase of both diameter and length of the anchorage did not significantly affect the bonding between concrete and GFRP bars. In addition, test results showed that the increase of anchorage number did not enhance the bond behavior of the anchorage system. Indeed, as the concrete compressive strength increased, the developed stress in GFRP bars increased. Moreover, the results have been compared with the empirical relations proposed by international codes and guidelines. The comparison showed that the suggested empirical relations by American Concrete Institute, Canadian Standard Association, Canadian Highway Bridge Design Code and Japan Society of Civil Engineers for the development length yield quite conservative results.

Applicability of Calculation Formulae of Impact Force by Tsunami Driftage

The aftermath of the Indian Ocean tsunami on 26 December 2004 triggered by the off Sumatra earthquake (magnitude “M” = 9.1), and the Great East Japan earthquake of 11 March 2011 off the Pacific coast of Tohoku (M = 9.0), evidence the secondary damage from driftage collision due to large tsunami waves. To prevent this type of damage, the establishment of methods for predicting driftage movement and calculating the impact force by driftage is necessary. Several numerical models have been developed to predict the driftage movement of objects. Every year, these improve in accuracy and usability. In contrast, there are many calculation formulae for calculating the impact force. However, since there are considerable differences between values calculated using these formulae, the reliability of each formula is unknown. Therefore, in this research, one team of the committee on tsunami research of the Japan Society of Civil Engineers summarizes the main calculation formulae of impact forces that have been proposed until 2019. In addition, for each type of driftage (driftwood, containers, cars, ships), we compare calculation values of these formulae with measured data of large-scale experiments. Finally, we check the range of calculation values for each formula up to 15 m/s in collision velocity and clarify then the following facts: (1) In the case of driftwood, the formulae of Matsutomi, Federal Emergency Management Agency (FEMA) and National Oceanic and Atmospheric Administration (NOAA), and American Society of Civil Engineers (ASCE) are most reliable; (2) In the case of containers, the formulae of Matsutomi, Arikawa et al., FEMA and NOAA, Ikeno et al., and ASCE are most reliable; (3) In the case of cars, the formulae of FEMA and NOAA, and ASCE are most reliable; (4) In the case of ships, the formulae of Mizutani, FEMA and NOAA, and ASCE are most reliable.

Bayesian optimization algorithm based support vector regression analysis for estimation of shear capacity of FRP reinforced concrete members

The use of fiber-reinforced polymer (FRP) rebars in lieu of steel rebars has led to some deviations in the shear behavior of concrete members. Several methods have been proposed to forecast the shear capacity of such members. Nonetheless, there are differences in the methods of considering the various parameters affecting shear capacity, and some of them provide widely scattered and conservative results. This paper presents a hybrid of the Bayesian optimization algorithm (BOA) and support vector regression (SVR) as a novel modeling tool for the prediction of the shear capacity of FRP-reinforced members with no stirrups. For this purpose, a large dataset of simply supported beams and unidirectional slabs reinforced with FRP were utilized. The model performance was assessed using several statistical performance indicators and compared with the Japan Society of Civil Engineers (JSCE), British Institution of Structural Engineers (BISE), Canadian Standard Association (CSA), and American Concrete Institute (ACI) design codes and guidelines, as well as some other artificial intelligence (AI) models. For development of the model, all the hyperparameters, i.e., kernel function type, epsilon, box constraint, and kernel scale, were optimized using the BOA technique. The k-fold cross validation approach was utilized to avoid overfitting of the model. It was found that the mean, median, standard deviation, minimum, maximum, and interquartile range of the developed hybrid model predictions are very close to the experimental results. The predicted results overlap the experimental data with a coefficient of determination of 95.5%. The plot of relative deviations and residual plots are scattered around the zero reference line with low deviation, which indicates that the model is reliable and valid. The error terms (e.g., mean absolute error, root mean square error) obtained for all specimens were 4.85 and 11.03, which are very low values. The correlation coefficient (R) and fractional bias (FB) were found to be 0.977 and 0.0033, which are very close to 1 and 0, respectively, thus implying a reliable prediction. The comparative investigations with other codes and guidelines show that the hybrid BOA–SVR model predictions are more accurate and robust than those of the other models.

Green Concrete for a Circular Economy: A Review on Sustainability, Durability, and Structural Properties.

A primary concern of conventional Portland cement concrete (PCC) is associated with the massive amount of global cement and natural coarse aggregates (NCA) consumption, which causes depletion of natural resources on the one hand and ecological problems on the other. As a result, the concept of green concrete (GC), by replacing cement with supplementary cementitious materials (SCMs) such as ground granulated blast furnace slag (GGBFS), fly ash (FA), silica fume (SF), and metakaolin (MK), or replacing NCA with recycled coarse aggregates, can play an essential role in addressing the environmental threat of PCC. Currently, there is a growing body of literature that emphasizes the importance of implementing GC in concrete applications. Therefore, this paper has conducted a systematic literature review through the peer-reviewed literature database Scopus. A total of 114 papers were reviewed that cover the following areas: (1) sustainability benefits of GC, (2) mechanical behavior of GC in terms of compressive strength, (3) durability properties of GC under several environmental exposures, (4) structural performance of GC in large-scale reinforced beams under shear and flexure, and (5) analytical investigation that compares the GC shear capacities of previously tested beams with major design codes and proposed models. Based on this review, the reader will be able to select the optimum replacement level of cement with one of the SCMs to achieve a certain concrete strength range that would suit a certain concrete application. Also, the analysis of durability performance revealed that the addition of SCMs is not recommended in concrete exposed to a higher temperature than 400 °C. Moreover, combining GGBFS with FA in a concrete mix was noticed to be superior to PCC in terms of long-term resistance to sulfate attack. The single most striking observation to emerge from the data comparison of the experimentally tested beams with the available concrete shear design equations is that the beams having up to 70% of FA as a replacement to OPC or up to 100% of RCA as a replacement to NCA were conservatively predicted by the equations of Japan Society of Civil Engineers (JSCE-1997), the American Concrete Institute (ACI 318-19), and the Canadian Standards Association (CSA-A23.3-14).

Engineering geological mapping for empirical design evaluation of Tunnel 10 of Jakarta - Bandung high-speed railway, Indonesia

An engineering geological mapping was carried out at the construction site of the Tunnel 10 of Jakarta Bandung High-Speed Railway to obtain data and information of the engineering geological conditions, particularly the rock masses. This research aims to determine the rock mass classes at the tunnel construction site and recommend the tunnel support system based on the Rock Mass Rating (RMR) and the Japan Society of Civil Engineers (JSCE) systems. This research is expected to better understand the rock mass classes, which were previously determined based on the newly applied Basic Quality (BQ) system for the tunnel support empirical design. The results showed that the research area consisted of young volcanic products, namely moderate to highly weathered tuff breccia and andesitic breccia. The uniaxial Compressive Strength (UCS) of rock mass varies between 1-25 MPa. The RMR value ranges from 21 to 40, indicating disintegrated and poor rock mass quality. The proposed tunnel support system is the combination of shotcrete, steel support for top heading and bench support, arch sidewall, and invert concrete.

Empirical analyses of excavation method and tunnel support system based on engineering geology of Tunnel No.8 at Jakarta – Bandung high-speed railway, West Bandung, Province of West Java, Indonesia

The Chinese Basic Quality (BQ) system was used to determine the rock mass classes and design tunnel support system of the Tunnel No.8 of the Jakarta-Bandung high-speed railway. As the BQ system is newly applied for tunnelling project in Indonesia and remains poorly understood, this research aims to determine rock mass classes at the tunnel construction site and propose the tunnel excavation method and support system alternative based on more widely used rock mass classifications of the Geological Strength Index (GSI) and Japan Society of Civil Engineers (JSCE) standard. Surface engineering geological mapping and evaluation of drill core samples were carried out to obtain accurate interpretation of subsurface engineering geological conditions, particularly the rock mass classes at the tunnel elevation. The results show that the tunnel construction area consists of very poor to fair classes of andesite breccia, tuff lapilli, and tuffaceous sandstone. The full-face method with auxiliary bench cut and multiple-bench cut method are to be applied at the tunnel sections consisting of rock mass classes CI and DII, respectively. The proposed tunnel support system is a combination of shotcrete, rock bolt, steel rib, and invert.

Engineering Ethics Education in Japan Society of Civil Engineers

Engineering Ethics Education in Japan Society of Civil Engineers

Analytical investigation of rectangular steel pipe shear connector

Rectangular steel pipe (RSP) which is a new kind of connector in a composite slab of steel–concrete has been proposed. Research on the shear properties of RSPs is limited, but such data are needed if RSPs are to be used as shear connectors in composite slabs. Here, a nonlinear finite-element (FE) model that accounts for the nonlinear material properties and the RSP–concrete interface is proposed. A comparison between the finite element method (FEM) results and the static push-out test data showed good agreement in terms of shear stiffness, shear capacity, and failure mode. This verified FE model was then used in a parametric study to investigate the effects of constraint in push-out test, concrete stiffness, concrete compressive strength, RSP dimensions, RSP thickness, and RSP welding length on RSP shear capacity. The analytical results showed that constraint, concrete strength, RSP dimensions, RSP thickness, and welding length all affected RSP shear capacity, whereas concrete stiffness showed light effects. The shear capacity obtained using the FE model was compared with the calculated result using the Japan Society of Civil Engineers (JSCE) equations for the shear capacity of L-shaped channels.

Effect of copper slag fine aggregate on corrosion processes and behavior in reinforced concrete prism specimen

This paper reports the result of experimental on the resistance to chloride diffusion and steel corrosion of concrete mixtures. A series of tests were performed to investigate the effect of copper slag as partial replacement of fine aggregate on corrosion processes and behavior in prism specimens. Chloride migration tests in steady-state were executed at the age of 28 and 91 days in accordance with Japan Society of Civil Engineers (JSCE) G571-2003 to determine the diffusion coefficient of chloride ions permeated through concrete specimens. In addition, some electrochemical tests were carried out through the repeated wet and dry (NaCl 10%) cycles up to 1 year to examines the probability of corrosion of steel bars in concrete, corrosion current density, and the rate of oxygen permeability. Based on the chloride migration test, which was obtained from the cumulative increase of chloride ion concentration, the results indicate that concrete with a longer curing period achieved lower chloride-ion concentration, thus suggesting that there is an increase in the resistance of concrete against chloride attack. The chloride penetration depth and distribution of chloride content in CUS prism specimens after exposure to wet and dry cycles for one year are almost similar to those of the OPC specimens. Thus, the durability performance of CUS concretes with respect to the resistance against chloride ingress was comparable to that of OPC concrete. Besides that, it is generally recognized that the incorporation of fly ash in blended cement by its the pozzolanic reaction of fly ash improves concrete protection against chloride-induced corrosion of steel bars by reducing its diffusivity and the rate of oxygen permeability.