Abstract
This study investigates the propagation of longitudinal waves in Glass-Fiber-Reinforced Polymer (GFRP) rock bolts
using numerical simulations. A two-dimensional axisymmetric model was used to represent the rock bolts. The simulations
examined the effects of grout and rock on wave propagation, focusing on how these materials influence the temporal and
spectral characteristics of the reflected longitudinal waves. The study also explored the impact of varying excitation frequencies
on wave characteristics. Results show that the wave velocity increases with the elastic modulus of either grout or rock, with
changes in the elastic modulus of grout only slightly affecting velocity, while changes in rock modulus significantly influence it.
Additionally, wave velocity in the rock bolt decreased gradually as rock thickness increased.
Key Words
dispersion; GFRP; longitudinal wave; rock bolt; wavelet transform
Address
Jung-Doung Yu:Department of Civil Engineering, Jeonbuk National University, Jeonju 54896, Korea
Namsun Kim:School of Civil, Environmental and Architectural Engineering, Korea University, Seoul 02841, Korea
Hyung-Koo Yoon:Department of Disaster Prevention and Safety Engineering, Daejeon University, Daejeon 34520, Korea
Thomas H.-K. Kang:Department of Architecture & Architectural Engineering, Seoul National University, Seoul 08826, Korea
Jong-Sub Lee:School of Civil, Environmental and Architectural Engineering, Korea University, Seoul 02841, Korea
Abstract
High-temperature creep poses a significant risk to the stability of steel structures, particularly when steel sectional
temperatures rise beyond 400°C. It is crucial to address this phenomenon in fire resistance analyses of steel structures
appropriately. This paper offers various design approaches to accommodate high-temperature creep in the analysis of steelframed structures. The first approach, termed the 'creep-marginal' scenario, suggests disregarding the high-temperature creep
strain in steel members experiencing low stress levels and sectional temperatures. In the 'creep-moderate' scenario, where the
high-temperature creep strain is considerable, it can be implicitly integrated into the analysis. For situations with substantial
creep strains, such as high stress levels and high temperatures, it is essential to explicitly incorporate creep into the fire resistance
analysis ('creep-significant' scenario). The feasibility of these approaches in addressing creep in fire resistance analyses is
demonstrated through three case studies involving steel-framed structures at various complexity levels.
Key Words
design recommendations; fire resistance; high-temperature creep; progressive collapse; steel structures
Address
Svetha Venkatachari:Department of Civil Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, Delhi 110016, India
Venkatesh Kodur:1) Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI 48824, USA
2) Department of Architectural & Urban Systems Engineering, Ewha Womans University, Seodaemun-gu, Seoul, South Korea
Abstract
Forensic-Information/Investigation-Modeling (FIM) faces significant challenges in efficiently segmenting largescale indoor spaces needed for detailed forensic analysis in the construction industry. Traditional segmentation methods are
computationally intensive and sensitive to the selection of initial seed points, often leading to inconsistent and inaccurate results.
To address these limitations, this study proposes an innovative 3-module approach to segment large-scale indoor space into
smaller functional spaces utilizing door points as seed points for region-growing methods alongside the typical point cloud
segmentation methods: RANSAC and DBSCAN. A case study was conducted on the sampled S3DIS (Stanford 3D Indoor
Scene) dataset, comprising 15 individual indoor spaces from Area 6. The results showed that the proposed approach effectively
segments large-scale indoor space into semantically meaningful individual rooms. The four performance metrics, Precision,
Recall, F1-Score, and IoU derived from the segmentation results of the proposed method mostly scored around 0.900, validating
the robustness of the proposed method. The guided-segmentation method contributes to the industry by facilitating effective and
prompt point cloud processing necessary for detailed analysis and BIM model generation.
Key Words
BIM; Forensics Information Modeling (FIM); point cloud segmentation; point cloud
Address
Seung Ho Song:Department of Civil, Environmental and Architectural Engineering, Korea University, Seongbuk-Gu, Seoul 02841, Republic of Korea
Heejae Ahn:Department of Civil, Environmental and Architectural Engineering, Korea University, Seongbuk-Gu, Seoul 02841, Republic of Korea
Changsu Lee:Department of Civil, Environmental and Architectural Engineering, Korea University, Seongbuk-Gu, Seoul 02841, Republic of Korea
Harim Kim:Department of Civil, Environmental and Architectural Engineering, Korea University, Seongbuk-Gu, Seoul 02841, Republic of Korea
Tae Sup Yun:School of Civil and Environmental Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul 03722, Republic of Korea
Goangseup Zi:Department of Civil, Environmental and Architectural Engineering, Korea University, Seongbuk-Gu, Seoul 02841, Republic of Korea
Hunhee Cho:Department of Civil, Environmental and Architectural Engineering, Korea University, Seongbuk-Gu, Seoul 02841, Republic of Korea
Abstract
The variability in the mechanical properties of reinforcing steel bars used in reinforced concrete elements affects the
performance of the different structural systems. This variability may lead to struggling to comply with the requirements of local
building codes. This study presents and discusses the uncertainty quantification of the mechanical parameters of the stress-strain
curve of steel reinforcing bars in Colombia. The database comprised results from experimental programs, including monotonic
axial tests on steel bars from different manufacturers in the country. A model was calibrated using the Bayesian estimation
framework, and the Monte Carlo Markov Chain method. Bayesian statistical analysis procedures were used to update the
Raynor model of the monotonic stress-strain curve of the steel. Distributions for parameters of the steel are then presented and
predictive check tests are performed for validation. The Bayesian statistical analysis allowed contrasting the mechanical
properties obtained experimentally with nominal properties specified by the manufacturers. The distributions and associated
variability for the main mechanical parameters of the rebars are presented and grouped by manufacturer and by bar size.
Address
Felipe Guerrero:School of Civil Engineering and Geomatic, Universidad del Valle, Cali 760032, Colombia
Albert R. Ortiz:1)School of Civil Engineering and Geomatic, Universidad del Valle, Cali 760032, Colombia
2)Colombian Earthquake Engineering Research Network, CEER, Colombia
Julian Carrillo:1)Colombian Earthquake Engineering Research Network, CEER, Colombia
2)Department of Civil Engineering, Universidad Militar Nueva Granada, Bogotá 110111, Colombia
Johannio Marulanda:School of Civil Engineering and Geomatic, Universidad del Valle, Cali 760032, Colombia
Peter Thomson:School of Civil Engineering and Geomatic, Universidad del Valle, Cali 760032, Colombia
Abstract
Aging and heavy rainfall can cause earth dams to undergo failure, which involves large displacements. Due to mesh
distortion, however, the finite element method (FEM) is unsuitable for analyzing such large displacements. As an alternative, the
material point method (MPM) ensures accurate simulation of large displacements, without the need for remeshing. This study
uses MPM to investigate the post-failure behaviors of earth dams with various geometries and under different rainfall intensities.
The MPM results are validated by comparing the MPM-derived pore water pressure with FEM-derived values for the same
model, and a close alignment is confirmed. Different failure patterns are observed depending on the geometry and rainfall
intensity. Under high water levels and rainfall conditions, the distributions and evolutions of the displacements and deviatoric
strain are initially concentrated at the dam toe and gradually propagated from the downstream slope toe to the dam crest.
Conversely, the distribution of pore water pressure remains relatively constant under high water levels, while rapid changes are
observed under rainfall conditions. The runout distance, crest settlement, and sliding volume increase with increasing dam
height, decreasing slope ratio, and increasing rainfall intensity. Therefore, MPM can be used as a promising tool for evaluating
the entire failure mechanisms and post-failure behaviors of unsaturated earth dams.
Key Words
earth dam; geometry; material point method; rainfall, unsaturated soil
Address
Dong-Ju Kim: School of Civil, Environmental and Architectural Engineering, Korea University,
145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
Geunwoo Park:School of Civil, Environmental and Architectural Engineering, Korea University,
145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
Jong-Sub Lee:School of Civil, Environmental and Architectural Engineering, Korea University,
145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
Thomas H.-K. Kang:Department of Architecture and Architectural Engineering, Seoul National University,
1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
Yong-Hoon Byun:Department of Agricultural Civil Engineering, Kyungpook National University,
80, Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea
Abstract
This study investigates the effects of elevated temperatures on the mechanical properties of concrete, which is an
important consideration in structural applications involving fire or thermal loading, such as buildings, bridges, and tunnels. The
objective of this research was to evaluate the behavior of concrete specimens under various temperatures (25°C to 750°C)
through a series of comprehensive laboratory tests, including Unconfined Compressive Strength (UCS), Split Tensile Strength
(STS), and Multi-Step Cyclic Loading (MSCL) tests. These tests were designed and carried out to assess the energy dissipation
and damping characteristics of concrete when subjected to cyclic and seismic loads. Additionally, Ultrasonic Pulse Velocity
(UPV) tests and Computed Tomography (CT) scans were carried out to quantify thermal damage and provide insight into the
resulting internal changes in concrete specimens. The study provides new insights into the cyclic behavior of thermally damaged
concrete, which is an area with significant practical applications but with limited existing studies. Results of this study
demonstrate that higher temperatures can significantly reduce the energy dissipation capability of concrete while increasing its
damping ratio. The UPV results showed that damage due to cyclic loading was lower, while the total damage was significantly
higher under the combined effect of temperature and cyclic loading. These findings can help improve the methodologies for
cyclic and seismic design of concrete structures after they have been subjected to elevated temperatures.
Key Words
concrete; cyclic loading; damping ratio; dynamic properties; elevated temperatures; energy dissipation
Address
Shayan Narani:School of Engineering, University of British Columbia, Kelowna, British Columbia, Canada
Pouria Zare:School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, USA
Sumi Siddiqua:School of Engineering, University of British Columbia, Kelowna, British Columbia, Canada
Kianoosh Hatami:School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, USA
Mohsen Abbaspour:School of Engineering, Meybod University, Meybod, Iran
Abstract
Expandable foam grout (EFG) is a cementitious mixture with relatively high flowability, high volume expansion,
and low long-term strength. EFG mixtures typically contain water, cement, bentonite, aluminum powder, and an alkali-free
accelerator. Aluminum powder induces volume expansion in EFG mixtures through chemical reactions with the cement paste,
resulting in hydrogen gas generation in the cement paste. Subsequently, gas retention establishes a porous structure as the
mixture loses its flowability through cement hydration (cement setting). The alkali-free accelerator plays a critical role in the
activation of cement hydration, depending on the accelerator content. Therefore, it is important to evaluate the effects of the
accelerator content on the volume expansion and strength of EFG mixtures because the hydration rates affect these
characteristics. This study experimentally observed the evolution of the expansion ratio and compressive strength of EFG
mixtures with various accelerator contents. The expansion ratio and compressive strength decreased with an increase in
accelerator content, partly because of the shortened setting time. Based on these results, the relationship between the accelerator
content of the EFG mixtures and their mechanical properties was established. Furthermore, the relationship between volume
expansion and compressive strength was determined.
Key Words
alkali-free accelerator, aluminum powder, compressive strength, expandable foam grout, volume expansion
ratio
Address
WooJin Han:School of Civil, Environmental and Architectural Engineering, Korea University,
145 Anam-ro, Seongbuk-gu, Seoul, 02841, South Korea
Dongsoo Lee:School of Civil, Environmental and Architectural Engineering, Korea University,
145 Anam-ro, Seongbuk-gu, Seoul, 02841, South Korea
Jong-Sub Lee:School of Civil, Environmental and Architectural Engineering, Korea University,
145 Anam-ro, Seongbuk-gu, Seoul, 02841, South Korea
Tae Sup Yun:School of Civil and Environmental Engineering, Yonsei University, 50, Yonsei-ro Seodaemun-gu, Seoul, 03722, South Korea
Jongchan Kim:Major of Civil Engineering, Department of Sustainable Engineering, Pukyong National University, Busan, 48513, South Korea
Abstract
One of the most critical issues in the field of construction, which has gained significant attention, particularly in the
last two decades, is the monitoring of structural conditions. Over time, structures may experience damage to their components
during use, which can worsen if not addressed. Various factors, such as the application of larger-than-expected forces,
unfavorable environmental conditions, severe weathering, design flaws, impacts, fatigue, and corrosion, can cause damage to
structures, leading to substantial changes in their dynamic properties. In this research, a new method, along with a novel damage
index, is introduced for detecting damage in concrete beams. The method processes structural response signals using the ChoiWilliams time-frequency function. Then, damage is identified using the X-index, and its location is determined. To assess the
proposed method, a reinforced concrete beam was constructed in the laboratory, and vibration tests were conducted under
various damage scenarios. The results demonstrate that the proposed method not only detects the presence of damage but also
accurately identifies its location and determines the damage's relative severity. In the proposed method, there is no need to
develop an analytical model, measure the input force, or remove noise from the signals. Another advantage of this method is the
relatively small number of sensors required.
Key Words
Choi-Williams function; concrete beam; condensed matrix methods; damage detection; deck of bridges
Address
Hamid Reza Ahmadi:Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, P.O. Box 55136-553, Iran
Vahid Haddadi:Department of Civil Engineering, Faculty of Engineering, University of Maragheh, Maragheh, P.O. Box 55136-553, Iran
Mahmoud Bayat:School of Architecture, The University of Texas at Arlington, Arlington, TX, USA
Abstract
This study evaluates the applicability of Rational Formula (RF) or Modified Rational Formula (MRF) in the
presence of storage effect. For this purpose, a storage-effect-considered MRF (MRFS) is derived, and its peak time and peak
flow are compared with those of MRF. Additionally, these models are compared with the Clark Model, where both the
uniformly-distributed and temporally-distributed rainfall based on the Huff method are considered (i.e., Clark-Uniform and
Clark-Huff). All of these models are then applied to artificial basins as well as to real basins. Results show that MRF estimates
the largest peak flow among the models, but is similar to that of Clark-Huff. The peak flow of MRF is much higher than those of
MRFS and Clark-Uniform. Both MRFS and Clark-Uniform are similar to each other in their peak times and peak flows. The
difference between MRF and MRFS increases as the storage effect increases, which becomes higher than 10% in case the
Russell coefficient is 0.32 or higher. Their difference is also maximized when the concentration time equals the rainfall duration,
which then decreases as the rainfall duration increases. Overall, it is verified that MRFS can be an alternative to the existing
Clark model if the temporal variability of rainfall is small. Also, if the rainfall duration is sufficiently long, MRF can produce a
reasonable design peak flow similar to that based on the Clark model.
Key Words
modified rational formula; rational formula; Russell coefficient; storage effect
Address
Jinwook Lee:Department of Civil, Environmental and Construction Engineering, College of Engineering,
University of Hawaii at Manoa, Honolulu, HI 96822, USA
Chulsang Yoo:School of Civil, Environmental and Architectural Engineering, College of Engineering, Korea University, Seoul 02841, Korea
Seungkwan Hong:School of Civil, Environmental and Architectural Engineering, College of Engineering, Korea University, Seoul 02841, Korea
