浅谈某斜拉桥钢桁梁拼装高强螺栓施工质量控制要点

本文结合某特大桥(斜拉桥)钢桁梁高强螺栓施工的质量管控情况,通过在该桥施工中担任监理工程师的工作经历,于2016年9月撰写本文,对钢桁梁现场拼安装过程中的高栓施工质量控制要点进行了整理、总结与介绍.

南京大胜关长江大桥高强度螺栓试验控制方案

介绍京沪高速铁路南京大胜关长江大桥在主桥钢梁架设中高强度螺栓(以下简称高栓)进场检验、工艺试验及施拧过程试验控制的方案。

Effects of Lingzhi (Ganoderma lucidum) on Hemorrheology Parameters and Symptoms of Hypertensive Patients with Hyperlipidemia and Sequelae of Cerebral Thrombosis

The effects of Lingzhi(Ganoderma lucidum)on hemorrheology parameters and symptoms of hypertensive patients with hyperlipidemia,sequelae of cerebral thrombosis and coronary heart disease are studied.The Lingzhi extract was given to 33 patients(15 male,18 female,65±8 years old)in dosage of 110mg qid po for 2 weeks.The blood viscosity was im- proved after treatment.The results showed that whole blood viscosity(at high shear rate and low shear rate)and plasma viscosity were significantly decreased(P<0.01).Lingzhi showed the effect of reducing blood pressure simultaneously.Several symptoms were also improved. However,there were no significant changes in haematocrit and erythrocyte sedimentation rate (P>0.05).In a few cases there occurred adverse reactions of palpitation and restlessness.

简支钢桁梁高强螺栓现场检测技术

一、前言高强螺栓(以下简称高栓)现在已大量使用在桥梁钢结构的连接施工中,普通螺栓可重复使用,但高栓不可重复使用,一般用于永久连接,对桥梁的安全运行起到了关键作用。尽管国内早已有相关技术标准对高栓的施工和检测有所规定,但高栓在现场的检测和使用过程中,仍经常发生问题,譬如高栓断裂等,影响了施工质量和桥梁安全,在此,本文结合简支钢桁梁的工程实际案例.

Investigation on Risk Factors of Cerebrocardiac Vascular Thrombotic Diseases in Patients with Obstructive Sleep Apnea Hypopnea Syndrome

Objective: To observe the risk factors of thrombosis in patients with obstructive sleep apnea hypopnea syndrome (OSAHS).Methods: From February 2001 to April 2003, 24 patients with moderate and severe OSAHS (OSAHS group) and 19 healthy adults (control group) were recruited. Their blood samples were drawn at 6∶00 and 16∶00 respectively for testing hemocrit, platelet aggregation (PAG), whole blood viscosity (WBV), prothrombin time (PT), activated partial thromboplastin time (APTT), plasma fibrinogen (Fng) and endothelin (ET).Results: There was a significantly higher hemocrit, WBV, Fng and ET as well as a significant shortening of PT and APTT at 6∶00 than that at 16∶00 in OSAHS group. However, there was no significant difference in all testing items between 6∶00 and 16∶00 in control group. The hemocrit, WBV, PAG, plasma Fng and ET were significantly higher, and PT and APTT were obviously shorter at 6∶00 in OSAHS group than those at 6∶00 in control group. A higher hemocrit, PAG, plasma Fng and ET, a longer PT and APTT were observed at 16∶00 in OSAHS group, compared with those at 16∶00 in control group.Conclusion: In OSAHS patients there were striking risk factors of thrombosis, which is more remarkable in the early morning than in the afternoon.

Predictive value of D-dimer for portal vein thrombosis after portal hypertension surgery in hepatitis B virus-related cirrhosis

AIM: To evaluate the predictive value of D-dimer as a predictive indicator of portal vein thrombosis (PVT) after portal hypertension surgery in hepatitis B virus-related cirrhosis. METHODS: A prospective study was carried out in 52 patients who had undergone surgery for portal hypertension in hepatitis B virus-related cirrhosis. Changes in perioperative dynamic D-dimer were observed. The sensitivity, specifi city, positive predictive values and negative predictive values of D-dimer were calculated, and ROC curves were analyzed. RESULTS: The D-dimer levels in the group developing postoperative PVT was signifi cantly higher than those in the group not developing PVT (P = 0.001), and the ROC semi-quantitative and qualitative analysis of D-dimer showed a moderate predictive value in PVT (semi- quantitative value Az = 0.794, P = 0.000; qualitative analysis: Az = 0.739, P = 0.001). CONCLUSION: Dynamic monitoring of D-dimer levels in patients with portal hypertension after surgery can help early diagnosis of PVT, as in cases where the D-dimer levels steadily increase and exceed 16 μg/mL, the possibility of PVT is very high.

Failure mechanism of bolting support and high-strength bolt-grouting technology for deep and soft surrounding rock with high stress

In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support is proposed to solve these problems. A calculation theory is established on the bond strength of the interface between the anchoring agent and surrounding rocks. An analysis is made on the influence law of different mechanical parameters of surrounding rocks on the interfacial bond strength. Based on the research, a new high-strength bolt-grouting technology is developed and applied on site. Besides, some helpful engineering suggestions and measures are proposed. The research shows that the serious deformation and failure, and the lower bond strength are the major factors causing frequent failures of bolt support. So, the bolt could not give full play to its supporting potential. It is also shown that as the integrity, strength, interface dilatancy and stress of surrounding rocks are improved, the bond strength will increase. So, the anchoring force on surrounding rocks can be effectively improved by employing an anchoring agent with high sand content, mechanical anchoring means, or grouting reinforcement. The new technology has advantages in a high strength, imposing pre-tightening force, and giving full play to the bolt supporting potential. Hence, it can improve the control effect on surrounding rocks. All these could be helpful references for the design of bolt support in deep underground mines.

Decompensated porto-pulmonary hypertension in a cirrhotic patient with thrombosis of portocaval shunt

We report a case of decompensated porto-pulmonary hypertension closely associated with the development of intra-portocaval shunt thrombosis. A woman with Laennec's cirrhosis was hospitalized because of severe dyspnea and edema. She underwent surgical portocaval anastomosis ten years ago. Imaging studies showed massive intra-shunt thrombosis,portal hypertension,ascites,pleuro-pericardial effusions and enlargement of right cardiac cavities. Cardiac catheterization allowed to rule out coronary and left-sided heart abnormalities and led to the diagnosis of pre-capillary pulmonary hypertension. Antithrombotic treatment with low molecular weight heparin was instituted. The management also included ACE inhibitors,spironolactone,low-salt diet and lactulose. The patient was discharged and three months later we observed the disappearance of edema,ascites and pleuro-pericardial effusions,a marked body weight reduction and improved dyspnea and liver function tests. A possible link between the development of intra-shunt thrombosis and clinical decompensation in our patient was hypothesized. In fact,it has been demonstrated that the increased portal pressure,caused by occlusion of portosystemic shunt,reduces renal plasma flow and increases systemic endothelin-1 concentration. In our patient the disappearance of edematous state and improved dyspnea observed after recanalization of the shunt strongly support this hypothesis.

Serum omentin and vaspin levels in cirrhotic patients with and without portal vein thrombosis

AIMTo investigate serum omentin and vaspin levels in cirrhotic patients; and to assess the relationship of these levels with hemostatic parameters, metabolic abnormalities, cirrhosis severity and etiology.METHODSFifty-one cirrhotic patients (17 with portal vein thrombosis) were analyzed. Serum omentin and vaspin levels were measured with commercially available direct enzyme-linked immunosorbent assays (ELISAs). To assess platelet activity, the following tests were performed using a MULTIPLATE®PLATELET FUNCTION ANALYZER: (1) an ADP-induced platelet activation test; (2) a cyclooxygenase dependent aggregation test (ASPI test); (3) a von Willebrand factor and glycoprotein Ib-dependent aggregation (using ristocetin) test (RISTO test); and (4) a test for thrombin receptor-activating peptide-6 induced activation of the thrombin receptor, which is sensitive to IIb/IIIa receptor antagonists.RESULTSOmentin, but not vaspin, serum concentrations were significantly decreased in patients with portal vein thrombosis (PVT) (P = 0.01). Prothrombin levels were significantly increased in patients with PVT (P = 0.01). The thrombin receptor activating peptide (TRAP) test results were significantly lower in the PVT group (P = 0.03). No significant differences in adipokines serum levels were found regarding the etiology or severity of liver cirrhosis assessed according to the Child-Pugh or Model of End-Stage Liver Disease (MELD) scores. There was a significant increase in the TRAP (P = 0.03), ASPI (P = 0.001) and RISTO high-test (P = 0.02) results in patients with lower MELD scores. Serum omentin and vaspin levels were significantly down-regulated in patients without insulin resistance (P = 0.03, P = 0.02, respectively). A positive relationship between omentin and vaspin levels were found both when all of the patients were analyzed (r = 0.41, P = 0.01) and among those with PVT (r = 0.94, P < 0.001).CONCLUSIONSerum omentin levels are increased in patients without PVT. Cirrhosis origin and grade do not affect omentin and vaspin levels. The analyzed adipokines do not influence platelet activity.

INVESTIGATION OF THROMBOMODULIN AND PLASMINOGEN ACTIVATOR INHIBITOR TYPE-I IN PREGNANCY INDUCED HYPERTENSION AND ITS CLINICAL SIGNIFICANCE

Objective. To measure the circulating levels of thrombomodulin (TM) and plasminogen activator inhibitor type- I (PAI- I) in women with pregnancy induced hypertension (PIH). Methods. Blood samples were drawn from 97 pregnant women in their third trimester, grouped as 25 mild PIH,26 moderate PIH,22 severe PIH and 24 normotensive healthy pregnant women for determining levels of TM by ELISA,PAI- I by colorimetric assay methods, and creatinine (Cr) in serum by biochemical method. Results. Circulating levels of TM, PAI- I and TM/Cr ratio increased with increasing severity of PIH. There were no significant differences between mild and normotensive pregnant women. The parameters were significantly changed in the moderate and severe PIH groups. Conclusion. TM and PAI- I may serve as meaningful clinical markers for the assessment of the endothelial damage in PIH, which is very important in evaluating and following the development of PIH.

Portal hypertension due to portal venous thrombosis:Etiology, clinical outcomes

The thrombophilia in adult life has major implications in the hepatic vessels. The resulting portal vein thrombosis has various outcomes and complications. Esophageal varices, portal gastropathy, ascites, severe hypersplenism and liver failure needing liver transplantation are known well. The newly formed collateral venous circulation showing itself as pseudocholangicarcinoma sign and its possible clinical reflection as cholestasis are also known from a long time. The management strategies for these complications of portal vein thrombosis are not different from their counterpart which is cirrhotic portal hypertension, but the prognosis is unquestionably better in former cases. In this review we present and discuss the portal vein thrombosis, etiology and the resulting dinical pictures. There are controversial issues in nomenclature, management （including anticoagulation problems）, follow up strategies and liver transplantation. In the light of the current knowledge, we discuss some controversial issues in literature and present our experience and our proposals about this group of patients.

Transhepatic catheter-directed thrombolysis for portal vein thrombosis after partial splenic embolization in combination with balloon-occluded retrograde transvenous obliteration of splenorenal shunt

A 66-year-old woman underwent partial splenic embolization （PSE） for hypersplenisrn with idiopathic portal hypertension （IPH）. One week later, contrast-enhanced CT revealed extensive portal vein thrombosis （PVT） and dilated portosystemic shunts. The PVT was not dissolved by the intravenous administration of urokinase. The right portal vein was canulated via the percutaneous transhepatic route under ultrasonic guidance and a 4 Fr. straight catheter was advanced into the portal vein through the thrombus. Transhepatic catheter-directed thrombolysis was performed to dissolve the PVT and a splenorenal shunt was concurrently occluded to increase portal blood flow, using balloon-occluded retrograde transvenous obliteration （BRTO） technique. Subsequent contrast-enhanced CT showed good patency of the portal vein and thrombosed splenorenal shunt. Transhepatic catheter-directed thrombolysis combined with BRTO is feasible and effective for PVT with portosystemic shunts.

Lubrication properties of silver-palladium alloy prepared by ion plating method for high temperature stud bolt

As a solid lubricant, silver-palladium (Ag-Pd) alloy coating was investigated for the application to high temperature stud bolt. A glue layer nickel (Ni) film was deposited on the surface of the hex bolt sample and then Ag-Pd alloy coating was performed on it using ion plating method. The friction coefficient of Ag-Pd alloy film coated bolt was lower than that of N-5000 oil coated bolt by the result of axial force measurement. The cyclic test of heat treatment was conducted to evaluate the durability of Ag-Pd alloy film coated bolt. In a cycle, sample was assembled into the block using torque wrench, followed by heating and disassembling. It was not successful to disassemble the N-5000 oil coated bolt from the block after only one cycle. However, the Ag-Pd alloy film coated bolt was able to be disassembled softly till 12 cycles.

Seismic behavior and mechanism analysis of innovative precast shear wall involving vertical joints

To study the seismic performance and load-transferring mechanism of an innovative precast shear wall(IPSW) involving vertical joints, an experimental investigation and theoretical analysis were successively conducted on two test walls. The test results confirm the feasibility of the novel joints as well as the favorable seismic performance of the walls, even though certain optimization measures should be taken to improve the ductility. The load-transferring mechanism subsequently is theoretically investigated based on the experimental study. The theoretical results show the load-transferring route of the novel joints is concise and definite. During the elastic stage, the vertical shear stress in the connecting steel frame(CSF) distributes uniformly; and each high-strength bolt(HSB)primarily delivers vertical shear force. However, the stress in the CSF redistributes when the walls develop into the elastic-plastic stage. At the ultimate state, the vertical shear stress and horizontal normal stress in the CSF distribute linearly; and the HSBs at both ends of the CSF transfer the maximum shear forces.

Percutaneous transarterial embolization of extrahepatic arteroportal fistula

Arteroportal fistula is a rare cause of prehepatic portal hypertension. A 44-year-old male with hepatitis virus C infection was admitted for acute variceal bleeding. Endoscopy showed the presence of large esophageal varices. The ultrasound revealed a mass near the head of pancreas, which was characterized at the color- Doppler by a turbulent flow, and arterialization of portal vein flow. CT scan of abdomen showed a large aneurysm of the gastroduodenal artery communicating into the superior mesenteric vein. The sinusoidal portal pressure measured as hepatic vein pressure gradient was normal, confirming the pre-hepatic origin of portal hypertension. The diagnosis of extrahepatic portal hypertension secondary to arteroportal fistula was established, and the percutaneous embolization was performed. Three months later, the endoscopy showed absence of esophageal varices and ascites. At the moment, the patient is in good clinical condition, without signs of portal hypertension.

A large congenital and solitary intrahepatic arterioportal fistula in an old woman

Arterioportal fistula(APF)is a rare cause of portal hypertension and may lead to death.APF can be congenital,post-traumatic,iatrogenic(transhepatic intervention or biopsy)or related to ruptured hepatic artery aneurysms.Congenital APF is a rare condition even in children.In this case report,we describe a 73-year-old woman diagnosed as APF by ultrasonography,computed tomography,and hepatic artery selective arteriography.The fistula was embolized twice but failed,and she still suffered from alimentary tract hemorrhage.Then,selective arteriography of the hepatic artery was performed again and venae coronaria ventriculi and short gastric vein were embolized.During the 2-year follow-up,the patient remained asymptomatic.We therefore argue that embolization of venae coronaria ventriculi and short gastric vein may be an effective treatment modality for intrahepatic APF with severe upper gastrointestinal bleeding.

Clinical characteristics of idiopathic portal hypertension

Idiopathic portal hypertension is one of the interesting causes of portal hypertension. Even in very developed medical centers, this disorder is still one of the most important misdiagnoses of clinical practice. To inexperienced physicians, presenting esophageal varices and upper gastrointestinal bleeding usually prompt an unfortunate diagnosis of cirrhosis. A heterogenous clinical presentation and progression of this disorder should be recognized by physicians, and management should be directed towards some specific problems confined to this disorder. Although a genetic basis and other factors are implicated in its pathogenesis, exact underlying mechanism(s) is (are) unknown. In this review, we discuss the heterogeneity of idiopathic portal hypertension, its etiopathogenesis, clinical presentation and management issues. With the expectation of an excellent prognosis, a practicing gastroenterologist should be aware that "not all varices mean cirrhosis".

Hospitalized ulcerative colitis patients have an elevated risk of thromboembolic events

AIM: To compare thromboembolism rates between hospitalized patients with a diagnosis of ulcerative colitis and other hospitalized patients at high risk for thromboembolism. To compare thromboembolism rates between patients with ulcerative colitis undergoing a colorectal operation and other patients undergoing colorectal operations. METHODS: Data from the National Hospital Discharge Survey was used to compare thromboembolism rates between (1) hospitalized patients with a discharge diagnosis of ulcerative colitis and those with diverticulitis or acute respiratory failure, and (2) hospitalized patients with a discharge diagnosis of ulcerative colitis who underwent colectomy and those with diverticulitis or colorectal cancer who underwent colorectal operations. RESULTS: Patients diagnosed with ulcerative colitis had similar or higher rates of combined venous thromboembolism (2.03%) than their counterparts with diverticulitis (0.76%) or respiratory failure (1.99%), despite the overall greater prevalence of thromboembolic risk factors in the latter groups. Discharged patients with colitis that were treated surgically did not have signifi cantly different rates of venous or arterial thromboembolism than those with surgery for diverticulitis or colorectal cancer.CONCLUSION: Patients with ulcerative colitis who do not undergo an operation during their hospitalization have similar or higher rates of thromboembolism than other medical patients who are considered to be high risk for thromboembolism.

Design methods of headed studs for composite decks of through steel bridges in high-speed railway

Aimed at two typical composite floor systems of through steel bridges in high speed railway,design methods of headed studs were put forward for different composite members through comparing and analyzing the structure,mechanical characteristics and transmission routes of deck loads.The simplified calculation models were brought out for the stud design of the longitudinal girders and transverse girders in the composite floor system of Nanjing Dashengguan Yangtze River Bridge (NDB).Studs were designed and arranged by taking the middle panel of 336 m main span for example.The results show that under deck loads,the longitudinal girders in the composite floor system of through steel bridges are in tension-bending state,longitudinal shear force on the interface is caused by both longitudinal force of "The first mechanical system" and vertical bending of "The second mechanical system",and studs can be arranged with equal space in terms of the shear force in range of 0.2d (where d is the panel length) on the top ends.Transverse girders in steel longitudinal and transverse girders-concrete slab composite deck are in compound-bending state,and out-of-plane bending has to be taken into account in the stud design.In orthotropic integral steel deck-concrete slab composite deck,out-of-plane bending of transverse girders is very small so that it can be neglected,and studs on the orthotropic integral steel deck can be arranged according to the structural requirements.The above design methods and simplified calculation models have been applied in the stud design of NDB.

Research on the mechanical property test of a new high-strength metal bolt

In order to study how to improve the overall performance of the operational metal bolt, based on the production process of an ordinary metal bolt used in understructure engineering, this paper focused on the existing problems of ordinary metal bolts identified by some survey and analysis. The results show that the structure of operational metal bolts is so unrea- sonable that the bolt tail is easily fractured by low load capacity. Furthermore, a new type of strong big-end metal bolt and its heat treatment and roughing processing technology were introduced. Through bolt tensile and metallographic tests, the property of the new big-end bolt was analyzed. The new findings indicate that after a special processing, the overall strength and plasticity of the bolt is greatly improved, and the grain of the bolt tail structure is refined, which would help build up favorable working conditions for bolt tails.