Effect of high-strength concrete on shear behavior of dry joints in precast concrete segmental bridges

Airong Liu,Haibo Jiang,Ying Chen,Tianlong Wang,Zhuangcheng Fang 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.5

The use of high-strength concrete (HSC) in precast concrete segmental bridges (PCSBs) can minimize the superstructure geometry and reduce beam weight, which can accelerate the construction speed. Dry joints between the segments in PCSBs introduce discontinuity and require special attention in design and construction. Cracks in dry joints initiate more easily than those in epoxy joints in construction period or in service. Due to the higher rupture strength of HSC, the higher cracking resistance can be achieved. In this study, shear behavior of dry joints in PCSBs was investigated by experiments, especially focusing on cracking resistance and shear strength of HSC dry joints. It can be concluded that the use of HSC can improve the cracking resistance, shear strength, and ductility of monolithic, single-keyed and three-keyed specimens. The experimental results obtained from tests were compared with the AASHTO 2003 design provisions. The AASHTO 2003 provision underestimates the shear capacity of single-keyed dry joint C50 and C70 HSC specimens, underestimates the shear strength of three-keyed dry joint C70 HSC specimens, and overestimates the shear capacity of three-keyed dry joint C50 HSC specimens.

Polymorphisms in Epigenetic and Meat Quality Related Genes in Fourteen Cattle Breeds and Association with Beef Quality and Carcass Traits

Liu, Xuan,Usman, Tahir,Wang, Yachun,Wang, Zezhao,Xu, Xianzhou,Wu, Meng,Zhang, Yi,Zhang, Xu,Li, Qiang,Liu, Lin,Shi, Wanhai,Qin, Chunhua,Geng, Fanjun,Wang, Congyong,Tan, Rui,Huang, Xixia,Liu, Airong,Wu, Asian Australasian Association of Animal Productio 2015 Animal Bioscience Vol.28 No.4

Improvement for carcass traits related to beef quality is the key concern in beef production. Recent reports found that epigenetics mediates the interaction of individuals with environment and nutrition. The present study was designed to analyze the genetic effect of single nucleotide polymorphisms (SNPs) in seven epigenetic-related genes (DNMT1, DNMT3a, DNMT3b, DNMT3L, Ago1, Ago2, and HDAC5) and two meat quality candidate genes (CAPN1 and PRKAG3) on fourteen carcass traits related to beef quality in a Snow Dragon beef population, and also to identify SNPs in a total of fourteen cattle populations. Sixteen SNPs were identified and genotyped in 383 individuals sampled from the 14 cattle breeds, which included 147 samples from the Snow Dragon beef population. Data analysis showed significant association of 8 SNPs within 4 genes related to carcass and/or meat quality traits in the beef populations. SNP1 (13154420A>G) in exon 17 of DNMT1 was significantly associated with rib-eye width and lean meat color score (p<0.05). A novel SNP (SNP4, 76198537A>G) of DNMT3a was significantly associated with six beef quality traits. Those individuals with the wild-type genotype AA of DNMT3a showed an increase in carcass weight, chilled carcass weight, flank thicknesses, chuck short rib thickness, chuck short rib score and in chuck flap weight in contrast to the GG genotype. Five out of six SNPs in DNMT3b gene were significantly associated with three beef quality traits. SNP15 (45219258C>T) in CAPN1 was significantly associated with chuck short rib thickness and lean meat color score (p<0.05). The significant effect of SNP15 on lean meat color score individually and in combination with each of other 14 SNPs qualify this SNP to be used as potential marker for improving the trait. In addition, the frequencies of most wild-type alleles were higher than those of the mutant alleles in the native and foreign cattle breeds. Seven SNPs were identified in the epigenetic-related genes. The SNP15 in CAPN1 could be used as a powerful genetic marker in selection programs for beef quality improvement in the Snow Dragon Beef population.

Polymorphisms in Epigenetic and Meat Quality Related Genes in Fourteen Cattle Breeds and Association with Beef Quality and Carcass Traits

Xuan Liu,Tahir Usman,Yachun Wang,Zezhao Wang,Xianzhou Xu,Meng Wu,Yi Zhang,Xu Zhang,Qiang Li,Lin Liu,Wanhai Shi,Chunhua Qin,Fanjun Geng,Congyong Wang,Rui Tan,Xixia Huang,Airong Liu,Hongjun Wu,Shixin Ta 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.4

Improvement for carcass traits related to beef quality is the key concern in beef production. Recent reports found that epigenetics mediates the interaction of individuals with environment and nutrition. The present study was designed to analyze the genetic effect of single nucleotide polymorphisms (SNPs) in seven epigenetic-related genes (DNMT1, DNMT3a, DNMT3b, DNMT3L, Ago1, Ago2, and HDAC5) and two meat quality candidate genes (CAPN1 and PRKAG3) on fourteen carcass traits related to beef quality in a Snow Dragon beef population, and also to identify SNPs in a total of fourteen cattle populations. Sixteen SNPs were identified and genotyped in 383 individuals sampled from the 14 cattle breeds, which included 147 samples from the Snow Dragon beef population. Data analysis showed significant association of 8 SNPs within 4 genes related to carcass and/or meat quality traits in the beef populations. SNP1 (13154420A>G) in exon 17 of DNMT1 was significantly associated with rib-eye width and lean meat color score (p<0.05). A novel SNP (SNP4, 76198537A>G) of DNMT3a was significantly associated with six beef quality traits. Those individuals with the wild-type genotype AA of DNMT3a showed an increase in carcass weight, chilled carcass weight, flank thicknesses, chuck short rib thickness, chuck short rib score and in chuck flap weight in contrast to the GG genotype. Five out of six SNPs in DNMT3b gene were significantly associated with three beef quality traits. SNP15 (45219258C>T) in CAPN1 was significantly associated with chuck short rib thickness and lean meat color score (p<0.05). The significant effect of SNP15 on lean meat color score individually and in combination with each of other 14 SNPs qualify this SNP to be used as potential marker for improving the trait. In addition, the frequencies of most wild-type alleles were higher than those of the mutant alleles in the native and foreign cattle breeds. Seven SNPs were identified in the epigenetic-related genes. The SNP15 in CAPN1 could be used as a powerful genetic marker in selection programs for beef quality improvement in the Snow Dragon Beef population.

Hypolipidemic effect of soluble dietary fibers prepared from Asparagus officinalis and their effects on the modulation of intestinal microbiota

Miansong Zhang,Mengke Yao,Airong Jia,Yaping Shi,Xinfeng Bai,Xue Liu,Tingting Cui,Xin Liu,Changheng Liu 한국식품과학회 2021 Food Science and Biotechnology Vol.30 No.13

The soluble dietary fiber from Asparagus officinalis(ASDF) was successively prepared using enzymolysiscombined with spray-drying technology. Highperformanceliquid chromatography analysis showed thatASDF contained two polysaccharide fractions with theaverage molecular weight of 2.77 9 105 and6.44 9 103 Da, and was composed of mannose, rhamnose,galacturonic acid, glucose, galactose, and arabinose with amolecular ratio of 19.93:1.02:1.94:32.17:1.00:1.91,respectively. ASDF showed potential in vitro antioxidantactivities. The oral administration of ASDF significantlyreduced the levels of total cholesterol, triglyceride, andlow-density lipoprotein cholesterol in HD-induced miceserum. Furthermore, 16S rRNA gene sequencing analysisshowed that ASDF significantly affected the compositionof intestinal microbiota, especially reducing the Firmicutes/Bacteroidotetes ratio and the relative abundances ofDesulfobacterota, Proteobacteria, Actinobacteriota andincreasing that of Muribaculaceae, Bacteroides, and Alloprevotella. These results demonstrated that the intake ofASDF could regulate intestinal microbiota and serum lipidlevels in hyperlipidemic conditions.

Experimental and numerical investigations on remaining strengths of damaged parabolic steel tubular arches

Yonghui Huang,Airong Liu,Yong-Lin Pi,Mark A. Bradford,Jiyang Fu 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.1

This paper presents experimental and numerical studies on effects of local damages on the in-plane elastic-plastic buckling and strength of a fixed parabolic steel tubular arch under a vertical load distributed uniformly over its span, which have not been reported in the literature hitherto. The in-plane structural behaviour and strength of ten specimens with different local damages are investigated experimentally. A finite element (FE) model for damaged steel tubular arches is established and is validated by the test results. The FE model is then used to conduct parametric studies on effects of the damage location, depth and length on the strength of steel arches. The experimental results and FE parametric studies show that effects of damages at the arch end on the strength of the arch are more significant than those of damages at other locations of the arch, and that effects of the damage depth on the strength of arches are most significant among those of the damage length. It is also found that the failure modes of a damaged steel tubular arch are much related to its initial geometric imperfections. The experimental results and extensive FE results show that when the effective cross-section considering local damages is used in calculating the modified slenderness of arches, the column bucking curve b in GB50017 or Eurocode3 can be used for assessing the remaining in-plane strength of locally damaged parabolic steel tubular arches under uniform compression. Furthermore, a useful interaction equation for assessing the remaining in-plane strength of damaged steel tubular arches that are subjected to the combined bending and axial compression is also proposed based on the validated FE models. It is shown that the proposed interaction equation can provide lower bound assessments for the remaining strength of damaged arches under in-plane general loading.

Interfacial mechanical behaviors of RC beams strengthened with FRP

Jiangdong Deng,Airong Liu,Peiyan Huang,Xiaohong Zheng 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.58 No.3

FRP-concrete interfacial mechanical properties determine the strengthening effect of RC beams strengthened with FRP. In this paper, the model experiments were carried out with eight specimens to study the failure modes and the strengthening effect of RC beams strengthened with FRP. Then a theoretical model based on interfacial performances was proposed and interfacial mechanical behaviors were studied. Finite element analysis confirmed the theoretical results. The results showed that RC beams strengthened with FRP had three loading stages and that the FRP strengthening effects were mainly exerted in the Stage III after the yielding of steel bars, including the improvement of the bearing capacity, the decreased ultimate deformation due to the sudden failure of FRP and the improvement of stiffness in this stage. The mechanical formulae of the interfacial shear stress and FRP stress were established and the key influence factors included FRP length, interfacial bond-slip parameter, FRP thickness, etc. According to the theoretical analysis and experimental data, the calculation methods of interfacial shear stress at FRP end and FRP strain at midspan were proposed. When FRP bonding length was shorter, interfacial shear stress at FRP end was larger that led to concrete cover peeling failure. When FRP was longer, FRP reached the ultimate strain and the fracture failure of FRP occurred. The theoretical results were well consistent with the experimental data.

Dynamic analysis of long-span cable-stayed bridges under wind and traffic using aerodynamic coefficients considering aerodynamic interference

Han, Wanshui,Liu, Huanju,Wu, Jun,Yuan, Yangguang,Chen, Airong Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.5

The aerodynamic characteristics of vehicles are critical to assess vehicle safety and passenger comfort for vehicles running on long span bridges in a windy environment. However, in previous wind-vehicle-bridge (WVB) system analysis, the aerodynamic interference between the vehicle and the bridge was seldom considered, which will result in changing aerodynamic coefficients. In this study, the aerodynamic coefficients of a high-sided truck on the ground (ground case) and a typical bridge deck (bridge deck case) are determined in a wind tunnel. The effects of existent structures including the bridge deck and bridge accessories on the high-sided vehicle's aerodynamic characteristics are investigated. A three-dimensional analytical framework of a fully coupled WVB system is then established based on the finite element method. By inputting the aerodynamic coefficients of both cases into the WVB system separately, the vehicle safety and passenger comfort are assessed, and the critical accidental wind speed for the truck on the bridge in a windy environment is derived. The differences in the bridge response between the windward case and the leeward case are also compared. The results show that the bridge deck and the accessories play a positive role in ensuring vehicle safety and improving passenger comfort, and the influence of aerodynamic interference on the response of the bridge is weak.

Seismic performances of steel reinforced concrete bridge piers

Jiangdong Deng,Airong Liu,Qicai Yu,Guoxing Peng 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.3

The quasi static test of the steel reinforced concrete (SRC) bridge piers and rigid frame arch bridge structure with SRC piers was conducted in the laboratory, and the seismic performance of SRC piers was compared with that of reinforced concrete (RC) bridge piers. In the test, the failure process, the failure mechanism, hysteretic curves, skeleton curves, ductility coefficient, stiffness degradation curves and the energy dissipation curves were analyzed. According to the M-Φ relationship of fiber section, the three-wire type theoretical skeleton curve of the lateral force and the pier top displacement was proposed, and the theoretical skeleton curves are well consistent with the experimental curves. Based on the theoretical model, the effects of the concrete strength, axial compression ratio, slenderness ratio, reinforcement ratio, and the stiffness ratio of arch to pier on the skeleton curve were analyzed.

Experimental Study on Shear Behavior of Precast Concrete Segmental Beams with Hybrid Tendons and Dry Joints

Haibo Jiang,Yuhong Li,Airong Liu,Li Chen,Yuanhang Chen,Jie Xiao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.10

A series of tests were carried out on nine specimens to improve the understanding of the shear behavior of precast concrete segmental beams (PCSBs) with hybrid tendons and dry joints. The influences of the tendon layout (hybrid tendons and external tendons), shear span ratio, and joint type (monolithic joints, and dry joints) on shear behavior of PCSBs were experimentally studied. The test results indicated that hybrid tendons slightly improved the shear strength and stiffness of PCSBs with dry joints compared to external tendons. The shear strengths of PCSBs with hybrid tendons and dry joints reduced with an increasing shear span ratio. Compared to monolithic beams with hybrid tendons, the dry joints slightly decreased the shear strength and enhanced the nonlinear behavior of PCSBs with hybrid tendons. The shear strengths of PCSBs and monolithic beams can be conservatively predicted by the AASHTO, Chinese code, and British Standard. The strut-and-tie model of prestressing force can accurately estimate the shear strengths of all the beams.

Horizontal Shear Behaviors of Normal Weight and Lightweight Concrete Composite T‑Beams

Zhuangcheng Fang,Haibo Jiang,Airong Liu,Jiahui Feng,Yuanhang Chen 한국콘크리트학회 2018 International Journal of Concrete Structures and M Vol.12 No.5

This paper presents the results of recent research on the interface shear behavior of normal weight and lightweight concrete composite T-beams. In the experimental program 12 beams and necessary control cylinders were tested to provide experimental cases with the variables of interface preparation, clamping stress and lightweight slab concrete strength. Compared with 7 equations developed previously, it has been found that those formulas, especially the ones from current AASHTO and ACI design codes, give a conservative theoretical prediction of horizontal shear capacity of composite T-beams. Based on the experimental results, a more accurate equation was developed to predict the interface shear transfer strength of composite concrete T-beam. By comparing the experimental results of previous beam tests and shear-friction push-off tests for different types of concrete with both rough and smooth interface published in literature, it has been found that the proposed formula is reliable in predicting the horizontal shear strength of concrete composite T-beams.