Generation and Application of A Standardized Load-Time History to Tubular T-joints in Offshore Platforms

Marine structures are mostly made of metals and always experience complex random loading during their service periods. The fatigue crack growth behaviors of metal materials have been proved from laboratory tests to be sensitive to the loading sequence encountered. In order to take account of the loading sequence effect, fatigue life prediction should be based on fatigue crack propagation（FCP） theory rather than the currently used cumulative fatigue damage（CFD） theory. A unified fatigue life prediction（UFLP） method for marine structures has been proposed by the authors＇ group. In order to apply the UFLP method for newly designed structures, authorities such as the classification societies should provide a standardized load-time history（SLH） such as the TWIST and FALSTAFF sequences for transport and fighter aircraft. This paper mainly aims at proposing a procedure to generate the SLHs for marine structures based on a short-term loading sample and to provide an illustration on how to use the presented SLH to a typical tubular T-joint in an offshore platform based on the UFLP method.

Recent progresses in the development of tubular segmented-in-series solid oxide fuel cells:Experimental and numerical study

Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell technologies.However,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas sealing.To solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output voltage.This work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical studies.Finally,the challenges and future development of tubular SIS-SOFCs are also discussed.The findings of this work can help guide the direction and inspire innovation of future development in this field.

Tubular Heat Enhancement Using Twisted Tape Inserts with Large Holes

Heat augmentation techniques play a vital role in the heating and cooling processes in industries,including solar collectors and many applications that utilize heat exchangers.Several studies are based on inserting fillers inside the tubes to enhance heat transfer.This investigation considered the effects of twisted tapes with large holes on a tubular heat exchanger’s(HX)heat transmission,pressure drop,and thermal boosting factor.In the experimental section,counter-swirl flow generators used twisted tapes with pairs of 1.0 cm-diameter holes and changes in porosity(Rp)at 1.30%and 2.70%.In the experiments,air was utilized as a working fluid in a tube with a circular cross-section.The turbulent flow was considered,with Reynolds numbers(Re)domain from 4800 to 9500,and a boundary condition with a uniform wall heat flux was constructed.The findings expound that when the number of holes rose,the Nusselt number(Nu),the factor of friction(f),and the thermal enhancement factor(η)all increased as well.Additionally,as the friction factor increased,the Nusselt number of the tape-equipped tube was noticeably higher.Additionally,it was discovered that the friction factor was between 70%and 94%lower than the values of the tube without tape,while the(Nu)was between 87%and 97%higher than the conventional tube values.The maximum value ofηis 89%.According to the experimental results,empirical correlations for Nu,f,andηwere also generated.

Transient out-of-plane distortion of multi-pass fillet welded tube to pipe T-joints

The out-of-plane distortion induced in a multi-pass circumferential fillet welding of tube to pipe under different weld sequences and directions was studied using Finite Element Method(FEM) based Sysweld software and verified experimentally. The FEM analyses consisted of thermal and mechanical analyses.Thermal analysis was validated with experimental transient temperature measurements. In the mechanical analysis, three different weld sequences and directions were considered to understand the mechanism of out-of-plane distortion in the tube to pipe T-joints. It was learnt that the welding direction plays a major role in minimizing the out-of-plane distortion. Further, during circumferential fillet welding of the tube to pipe component, the out-of-plane distortion generated in the x direction was primarily influenced by heat input due to the start and stop points, whereas the distortion in the z direction was influenced by time lag and welding direction. The FEM predicted distortion was compared with experimental measurements and the mechanism of out-of-plane distortion was confirmed.

Self-assembly synthesis of phosphorus-doped tubular g-C_(3)N_(4);Ti_(3)C_(2)MXene Schottky junction for boosting photocatalytic hydrogen evolution

Establishing highly effective charge transfer channels in carbon nitride(g-C_(3)N_(4)) to enhance its photocatalytic activity is still a challenging issue.Herein,the delaminated 2D Ti_(3)C_(2) MXene nanosheets were employed to decorate the P-doped tubular g-C_(3)N_(4)(PTCN)for engineering 1D/2D Schottky heterojunction(PTCN/TC)through electrostatic self-assembly.The optimized PTCN/TC exhibited the highest hydrogen evolution rate(565 μmol h^(-1)g^(-1)),which was 4.3 and 2.0-fold higher than pristine bulk g-C_(3)N_(4) and PTCN,respectively.Such enhancement may be primarily attributed to the phosphorus heteroatom doped and unique structure of 1D/2D g-C_(3)N_(4)/Ti_(3)C_(2) Schottky heterojunction,enhancing the light-harvesting and charges’separation.One-dimensional pathway of g-C_(3)N_(4) tube and built-in electric field of interfacial Schottky effect can significantly facilitate the spatial separation of photogenerated charge carriers,and simultaneously inhibit their recombination via Schottky barrier.In this composite,metallic Ti_(3)C_(2) was served as electrons sink and photons collector.Moreover,ultrathin Ti_(3)C_(2) flake with exposed terminal metal sites as a co-catalyst exhibited higher photocatalytic reactivity in H2 evolution compared to carbon materials(such as reduced graphene oxide).This work not only proposed the mechanism of tubular g-C_(3)N_(4)/Ti_(3)C_(2) Schottky junction in photocatalysis,but also provided a feasible way to load ultrathin Ti_(3)C_(2) as a co-catalyst for designing highly efficient photocatalysts.

Albumin-bound kynurenic acid is an appropriate endogenous biomarker for assessment of the renal tubular OATs-MRP4 channel

Renal tubular secretion mediated by organic anion transporters(OATs)and the multidrug resistanceassociated protein 4(MRP4)is an important means of drug and toxin excretion.Unfortunately,there are no biomarkers to evaluate their function.The aim of this study was to identify and characterize an endogenous biomarker of the renal tubular OATs-MRP4 channel.Twenty-six uremic toxins were selected as candidate compounds,of which kynurenic acid was identified as a potential biomarker by assessing the protein-binding ratio and the uptake in OAT1-,OAT3-,and MRP4-overexpressing cell lines.OAT1/3 and MRP4 mediated the transcellular vectorial transport of kynurenic acid in vitro.Serum kynurenic acid concentration was dramatically increased in rats treated with a rat OAT1/3(rOAT1/3)inhibitor and in rOAT1/3 double knockout(rOAT1/3^(-/-))rats,and the renal concentrations were markedly elevated by the rat MRP4(rMRP4)inhibitor.Kynurenic acid was not filtered at the glomerulus(99%of albumin binding),and was specifically secreted in renal tubules through the OAT1/3-MRP4 channel with an appropriate affinity(Km)(496.7 mM and 382.2 mM for OAT1 and OAT3,respectively)and renal clearance half-life(t1/2)in vivo(3.7±0.7 h).There is a strong correlation in area under the plasma drug concentration-time curve(AUC0et)between cefmetazole and kynurenic acid,but not with creatinine,after inhibition of rOATs.In addition,the phase of increased kynurenic acid level is earlier than that of creatinine in acute kidney injury process.These results suggest that albumin-bound kynurenic acid is an appropriate endogenous biomarker for adjusting the dosage of drugs secreted by this channel or predicting kidney injury.

Dynamic Analysis and Parametric Optimization of Telescopic Tubular Mast Applied on Solar Sail

Large-scale solar sails can provide power to spacecraft for deep space exploration.A new type of telescopic tubular mast(TTM)driven by a bistable carbon fiber-reinforced polymer tube was designed in this study to solve the problem of contact between the sail membrane and the spacecraft under light pressure.Compared with the traditional TTM,it has a small size,light weight,high extension ratio,and simple structure.The anti-blossoming and self-unlocking structure of the proposed TTM was described.We aimed to simplify the TTM with a complex structure into a beam model with equal linear mass density,and the simulation results showed good consistency.The dynamic equation was derived based on the equivalent model,and the effects of different factors on the vibration characteristics of the TTM were analyzed.The performance parameters were optimized based on a multiobjective genetic algorithm,and prototype production and load experiments were conducted.The results show that the advantages of the new TTM can complete the deployment of large-scale solar sails,which is valuable for future deep space exploration.

ELABELA protects against diabetic kidney disease by activating high glucose-inhibited renal tubular autophagy

ELABELA(ELA),an endogenous ligand of the apelin receptor(also known as apelin peptide jejunum[APJ]),has been shown to decrease in the plasma of patients with diabetic kidney disease(DKD).In the current study,we explored the potential function as well as the underlying mechanisms of ELA in DKD.We first found that the ELA levels were decreased in the kidneys of DKD mice.Then,we found that ELA administration mitigated renal damage and downregulated the expression of fibronectin,collagenⅣ,and transforming growth factor-β1 in the db/db mice and the high glucose cultured HK-2 cells.Furthermore,the autophagy markers,Beclin-1 and LC3-Ⅱ/LC3-Ⅰratio,were significantly impaired in DKD,but the ELA treatment reversed these alterations.Mechanistically,the inhibitory effects of ELA on the secretion of fibrosis-associated proteins in high glucose conditions were blocked by pretreatment with 3-methyladenine(an autophagy inhibitor).In summary,these in vivo and in vitro results demonstrate that ELA effectively protects against DKD by activating high glucose-inhibited renal tubular autophagy,potentially serving as a novel therapeutic candidate for DKD.

Seismic behavior of steel tubular bridge columns equipped with low-yield-point steel plates in the root replaceable pier

To enable rapid recovery of a steel bridge column after an earthquake,a novel tubular-section steel bridge column equipped with low-yield-point(LYP)steel tubular plates in the root replaceable pier is proposed.For the purpose of discussing the seismic behavior of the novel steel bridge column,quasi-static tests and finite element simulation analyses of the specimens were carried out.The effects of parameters such as the axial compression ratio,eccentricity,and thickness and material strength of the tubular plate in the energy-dissipating zone are discussed.Experimental results from seven specimens that were subjected to four failure modes are presented.The damage to the quasi-static specimens is localized to the replaceable energy-dissipating pier.The seismic behavior of the novel steel bridge columns is significantly influenced by the axial compression ratio and eccentricity of specimens.Numerical results show that the high stress area of the specimens is mainly concentrated in the connection zone between the LYP steel tubular plate and the bottom steel plate,which is consistent with the position of the quasi-static specimen when it was prone to fracture.Finally,a calculation formula is proposed to facilitate the capacity prediction of this new steel tubular bridge column under repeated loading.

Compressive Strength of Tubular Members with Combined Pitting Corrosion and Crack Damage

Tubular members subject to combined pitting corrosion and crack damage were numerically studied to clarify the reduction of ultimate strength and failure behavior,based on numerical models validated against available experi-ments.The effects of length,location and inclined angle of a crack under combined damage were studied to disclose the mechanism of interaction between the crack and corrosion pits.The methods,named as linear superposition directly accumulating the effects of solo crack and solo pitting damage,as well as crack projection transferring an inclined crack to a transverse one,were discussed and verified in the view of assessing ultimate strength of tubular members with combined damage.It was shown that the former is practical but complex while the next always over-estimates the residual strength.Besides,the location and inclined angle of a crack have a subtle effect on the reduction of ultimate strength under combined damage,especially at higher level of pitting damage,due to the synergistic effect between corrosion pits and cracks.Such effect can lead to early occurrence of plasticity and local buckling by inducing stress interaction between crack tips and pits,and causing more significant strength reduction compared with a solo type of damage.A practical method was proposed to determine the loss ratio of cross-sectional area on the equivalent weakest section of a damaged member.Based on the loss ratio,a formula was presented to predict the ultimate strength of damaged members with combined damage,showing good applicability.

Clinical, Etiological and Progressive Aspects of Acute Tubular Necrosis of Toxic Origin at the Brazzaville University Hospital Center

Background and Objectives: Acute tubular necrosis (ATN) is the second cause of acute kidney injury (AKI) in an intra-hospital environment. The toxic origin is avoidable. Our objectives were to determine the toxic substances at the origin of ATN at the Brazzaville University Hospital and determine the evolving aspects and the factors associated with it. Patients and Methods: We carried out a 12-month from June 20, 2022 to June 30, 2023. It was a prospective observational study in the Nephrology Department of Brazzaville University Hospital Center. The diagnosis of ATN was done in the presence of AKI occurring in the context of taking nephrotoxic substances with negative albuminuria. Cases of ATN aggravating CKD were excluded. Data analysis was done with Epi-Info 7.2 software. Results: We identified 63 cases of AKI on toxic ATN. Their average age was 47 ± 19 years with a male predominance of 60.2%. The 3 main toxicants incriminated were: herbal medicine (49.2%), Gentamycin (17.5%) and non-steroidal anti-inflammatory drugs (14.3%). An indication for hemodialysis was made in 43 patients (68.2%), the evolution was marked by a cure in 29 patients (46.1%), 10 (15.9%) became chronic kidney failure, 19 (30.1%) died, 5 (7.9%) were lost to follow-up. The main factor for non-healing is anuria (p Conclusion: The main cause of toxic ATN at Brazzaville University Hospital is herbal medicine. The death rate is high there.

Decreased TRPM7 alleviates high glucose-induced renal tubular epithelial cell injury by inhibiting the HMGB1/TLR4 signaling pathway

Objective:To explore the regulatory mechanism of transient receptor potential melastatin-7(TRPM7)in high glucose-induced renal tubular epithelial cell injury.Methods:The expression of TRPM7 in the serum of diabetic nephropathy patients and high glucose-induced HK-2 cells was detected by RT-qPCR.Then,the TRPM7 interference vector was constructed,and the downstream high mobility group box 1(HMGB1)/Toll-like receptor 4(TLR4)signaling pathway proteins were detected.Next,in addition to interference with TRPM7 expression,overexpression of HMGB1 in high glucose-induced HK-2 cells was performed.Cell activity,apoptosis,oxidative stress levels,and inflammation levels were determined by CCK8,TUNEL,Western blotting,immunofluorescence and related kits.Results:TRPM7 expression was upregulated in the serum of diabetic nephropathy patients and high glucose-induced HK-2 cells.Interference with TRPM7 reduced cell damage,epithelial-mesenchymal transition,oxidative stress,and inflammatory response in high glucose-induced HK-2 cells via inhibiting the HMGB1/TLR4 signaling pathway.However,the effects induced by TRPM7 silencing were abrogated by HMGB1 overexpression.Conclusions:Decreased TRPM7 alleviates high glucose-induced renal tubular epithelial cell injury by inhibiting the HMGB1/TLR4 signaling pathway.Further animal experiments and clinical trials are warranted to verify its effect.

Incomplete distal renal tubular acidosis uncovered during pregnancy:A case report

BACKGROUND Renal tubular acidosis(RTA)is a renal cause of non-anion-gap metabolic acidosis characterized by low urinary ammonia excretion.This condition has a low prevalence,and various congenital and acquired etiologies.To date,only a few cases of idiopathic RTA uncovered during pregnancy have been reported.CASE SUMMARY A previously healthy 32-year-old Korean woman at 30 wk of gestation was admitted to Pusan National University Hospital with preterm labor.At admission,the patient presented with hypokalemia,non-anion-gap metabolic acidosis,and nephrocalcinosis.Distal RTA was diagnosed based on laboratory blood and urine findings and imaging examinations.Various tests,including next-generation gene sequencing panels for nephropathy,were performed to determine the etiology of the disease,which indicated that it was idiopathic.The patient received sodium bicarbonate and potassium chloride supplementation.After 3 wk,she delivered a baby who was subsequently diagnosed with corpus callosum agenesis and colpocephaly.During regular follow-ups for 6 mo postpartum,her hypokalemia and metabolic acidosis were gradually resolved,and medications eventually discontinued.CONCLUSION Herein we describe a case of idiopathic distal RTA discovered during pregnancy.Hypokalemia and metabolic acidosis resolved spontaneously after delivery.

Recent applications and chiral separation development based on stationary phases in open tubular capillary electrochromatography(2019–2022)

Capillary electrochromatography(CEC)plays a significant role in chiral separation via the double separation principle,partition coefficient difference between the two phases,and electroosmotic flow-driven separation.Given the distinct properties of the inner wall stationary phase(SP),the separation ability of each SP differs from one another.Particularly,it provides large room for promising applications of open tubular capillary electrochromatography(OT-CEC).We divided the OT-CEC SPs developed over the past four years into six types:ionic liquids,nanoparticle materials,microporous materials,biomaterials,non-nanopolymers,and others,to mainly introduce their characteristics in chiral drug separation.There also added a few classic SPs that occurred within ten years as supplements to enrich the features of each SP.Additionally,we discuss their applications in metabolomics,food,cosmetics,environment,and biology as analytes in addition to chiral drugs.OT-CEC plays an increasingly significant role in chiral separation and may promote the development of capillary electrophoresis(CE)combined with other instruments in recent years,such as CE with mass spectrometry(CE/MS)and CE with ultraviolet light detector(CE/UV).

Analysis of inhomogeneity of solidified microstructure of continuous casting copper tubular billet based on factor analysis

The horizontal continuous casting process,the initial step in TP2 copper tubular processing,directly determines the microstructure and properties of copper tubular.However,the process parameters of the continuous casting characterize time variation,multiple disturbances and strong coupling.As a consequence,their influence on a casting billet is difficult to be determined.Due to the above issues,the common factor and special factor analysis of the factor analysis model were used in this study,and the casting experiment and billet metallographic experiment were carried out to diagnose and analyze the reason of the microstructure inhomogeneity.The multiple process parameters were studied and classified using common factor analysis,2 the cast billets with abnormal microstructures were identified by GT^(2) statistics,and the most important factors affecting the microstructural homogeneity were found by special factor analysis.The calculated and experimental results show that the principal parameters influencing the inhomogeneity of solidified microstructure are the primary inlet water pressure and the primary outlet water temperature.According to the consequence of the above investigation,the inhomogeneity of the copper billet microstructure can be effectively improved when the process parameters are controlled and adjusted.

Renal calcification in children with renal tubular acidosis:What a paediatrician should know

Renal tubular acidosis(RTA)can lead to renal calcification in children,which can cause various complications and impair renal function.This review provides pediatricians with a comprehensive understanding of the relationship between RTA and renal calcification,highlighting essential aspects for clinical manage-ment.The article analyzed relevant studies to explore the prevalence,risk factors,underlying mechanisms,and clinical implications of renal calcification in children with RTA.Results show that distal RTA(type 1)is particularly associated with nephrocalcinosis,which presents a higher risk of renal calcification.However,there are limitations to the existing literature,including a small number of studies,heterogeneity in methodologies,and potential publication bias.Longitudinal data and control groups are also lacking,which limits our understanding of longterm outcomes and optimal management strategies for children with RTA and renal calcification.Pediatricians play a crucial role in the early diagnosis and management of RTA to mitigate the risk of renal calcification and associated complications.In addition,alkaline therapy remains a cornerstone in the treatment of RTA,aimed at correcting the acid-base imbalance and reducing the formation of kidney stones.Therefore,early diagnosis and appropriate therapeutic interventions are paramount in preventing and managing renal calcification to preserve renal function and improve long-term outcomes for affected children.Further research with larger sample sizes and rigorous methodologies is needed to optimize the clinical approach to renal calcification in the context of RTA in the pediatric population.

枸杞多糖通过激活Nrf2/HO-1通路保护HK-2细胞氧化损伤的作用

目的分析枸杞多糖(LBP)干预对氧化损伤的人肾小管上皮细胞(HK-2)内的核因子E2相关因子2(Nrf2)/血红素氧合酶-1(HO-1)通路蛋白表达的变化,探索LBP拮抗HK-2细胞氧化损伤的分子机制。方法采用过氧化氢诱导HK-2细胞制备氧化损伤细胞模型,HK-2被分成4组:正常组、LBP组、氧化损伤组及LBP干预组。观察4组细胞的长势和形态变化;细胞活力测定法比较每组细胞的存活率;比色法分析氧化产物丙二醛(malondialdehyde,MDA)含量以及超氧化物歧化酶(superoxide dismutase,SOD)和谷胱甘肽过氧化酶(GSH-Px)的水平;免疫印迹技术检测细胞内Nrf2/HO-1通路蛋白Nrf2、HO-1的相对水平。结果正常组和LBP组相比,两组的细胞长势、形态和存活率,细胞产生MDA的量、SOD和GSH-Px的水平,通路蛋白Nrf2、HO-1的相对水平均无明显差异(均P>0.05);氧化损伤组和正常组相比,细胞皱缩变圆并脱落、贴壁细胞变少,存活率减少、MDA量增加、SOD和GSH-Px降低,通路蛋白Nrf2、HO-1的相对值下降(均P<0.05);LBP干预组和氧化损伤组相比,细胞长势、形状恢复、贴壁细胞较多,存活率增加、MDA量减少、SOD和GSH-Px升高,通路蛋白Nrf2、HO-1的相对值升高(均P<0.05)。结论枸杞多糖能通过激活Nrf2/HO-1通路提高HK-2细胞的抗氧化酶活性达到减轻细胞氧化损伤的目的。

姜黄素调控TLR4/NF-κB和NRF2/HO-1信号通路改善草酸钙晶体诱导的小鼠肾损伤

目的探讨姜黄素(curcumin,CUR)对乙醛酸诱导的小鼠肾结石形成模型中肾损伤的保护作用及其机制。方法通过连续腹腔注射乙醛酸,建立小鼠肾结石形成模型。以一水草酸钙(calcium oxalate monohydrate,COM)诱导HK-2细胞作为体外模型。小鼠模型经CUR作用后,测定肾小管损伤、炎症细胞因子水平,研究CUR对小鼠肾结石的保护作用;CUR对COM诱导HK-2作用后,检测细胞活力及炎症因子;Western blot检测小鼠肾组织和HK-2细胞Toll样受体4(TLR4)/核因子κB(NF-κB)和核因子红血球相关因子2(NRF2)/血红素加氧酶1(HO-1)通路相关蛋白;为进一步探讨CUR对TLR4/NF-κB和NRF2/HO-1通路的调控作用,采用NRF2抑制剂ML385和TLR4激动剂CCL-34分别作用于COM诱导的HK-2细胞,以进行功能增益和功能丧失检测。结果CUR改善小鼠肾结石形成模型损伤,抑制炎症和抗氧化作用;促进COM诱导HK-2细胞的活力,抑制炎症因子的表达。CUR抑制TLR4/NF-κB通路中蛋白的表达,促使NRF2从细胞质转移到细胞核,并促进HO-1的表达。ML385和CCL-34分别抵消CUR对COM诱导HK-2细胞抗炎作用的影响。结论CUR通过调控小鼠肾结石形成模型TLR4/NF-κB和NRF2/HO-1通路改善肾损伤。

过表达线粒体蛋白磷酸酶2C对人肾小管上皮细胞转录组的影响

背景:课题组前期研究发现相较于野生型小鼠,线粒体蛋白磷酸酶2C(protein phosphatase 2Cm,PP2Cm)基因缺失小鼠明显发生肾功能衰竭的症状,因此推测PP2Cm可能在肾脏纤维化发展过程中发挥重要保护作用,然而其分子机制尚不明确。目的:探究PP2Cm基因对于人肾小管上皮细胞转录组的影响。方法:培养人肾小管上皮细胞,用质粒将PP2Cm基因转染进入人肾小管上皮细胞,荧光定量PCR实验和Western blot实验检测细胞中PP2Cm的表达,随后分别提取细胞RNA进行转录组测序,寻找转染组和对照组之间的差异性表达基因,利用生物信息学方法进一步对所得的差异基因进行GO分析和KEGG分析。结果与结论:通过测序分析,与未转染空白细胞相比,在转染PP2Cm基因的人肾小管上皮细胞中存在796个差异性表达基因,其中553个下调基因,243个上调基因,GO分析结果显示,上调表达的基因显著富集在细胞生物合成过程、蛋白质翻译、内在凋亡信号通路等;下调表达的基因显著富集在内皮细胞增殖、细胞黏附等信号通路;KEGG分析结果显示,显著上调表达的基因富集在氨基酸代谢、生物合成等代谢相关信号通路;下调表达的基因显著富集在泛酸和辅酶A的生物合成等信号通路。结果表明,PP2Cm过表达可以影响肾小管上皮细胞的一系列生物学过程相关的多条信号通路,可能在氨基酸代谢、生物合成等代谢相关信号通路中起重要作用。

RPC外包方钢管混凝土柱轴压受力性能研究

为了研究活性粉末混凝土(Reactive powder concrete,RPC)外包方钢管混凝土柱的轴压受力性能,以RPC厚度和长细比为参数,对6根构件开展轴压试验研究,探讨该类组合柱的破坏模式、受力机理、套箍效应和承载力。试验结果表明:外层RPC可为内部方钢管混凝土柱提供较强的约束力,在受力后期套箍效应凸显。随着RPC厚度的增加,组合柱的承载力逐渐提高;随着组合柱长细比的增大,虽然其弹性刚度和承载力逐渐降低,但延性改善。采用ABAQUS软件建立RPC外包方钢管混凝土柱的有限元模型,分析RPC强度、RPC厚度、钢管强度等级、含钢率、内部混凝土强度和长细比等参数对组合柱承载力的影响规律,可得方钢管混凝土柱发挥系数的变化幅值为0.78~1.01。在试验研究、有限元参数分析和理论探讨的基础上,借鉴钢管混凝土结构技术规范,提出了RPC外包方钢管混凝土轴压短柱和长柱的承载力简化计算方法,公式计算值与已有数据样本吻合良好。