IL METODO DEGLI SCHEMI ELASTICI PARZIALI NELLA COSTRUZIONE A SBALZO DEI PONTI AD ARCO

In questo lavoro viene presentato uno studio sulle sequenze di tesatura degli stralli nei ponti ad arco costruiti per sbalzi successivi con l’ausilio di tiranti provvisori. In particolare viene presentato il metodo degli schemi elastici parziali, proposto per la determinazione degli sforzi iniziali nei cavi. Tale metodologia è stata dapprima applicata sui ponti strallati e viene estesa in questo studio al caso dei ponti ad arco costruiti per sbalzi successivi. La trattazione teorica è seguita da un’applicazione numerica su un caso studio di un ponte ad arco in calcestruzzo

CREEP EFFECTS AND STRESS ADJUSTMENTS IN CABLE-STAYED BRIDGES WITH CONCRETE DECK

In construction stages of cable-stayed bridges with prestressed concrete deck, the influence of creep on stresses and strains is very important in order to foresee the final patterns of internal forces and displacements. In cantilever construction, the concrete deck can be considered, in each stage, as a continuous beam resting on elastic restraints, which modify with successive additions of new segments, until the last one has been assembled. In these stages stress relaxation in concrete occurs as well as vertical displacements increase. Ehen structure has been closed by inserting midspan segment, stress redistribution begins, due to creep. Deformation and internal force development in construction and service life modify stay stresses such as deck and pylon final profiles. It is necessary to prevent undesirable deformed shape of deck and pylon and to control the final stress pattern of deck and stays. The requested final geometry of the bridge is reached by adjusting stay axial forces during construction. A study is presented in which, by taking into account creep effects, the optimization in terms of deck and pylon deformed shape can be achieved through a sequence of stay force adjustments during construction stages. The presented analysis is based on the theory of aging linear viscoelasticity in order to give a useful tool for the conceptual design of cable-stayed bridges with concrete deck. The proposed procedure allows engineers to design by reducing and avoiding creep effects instead of calculating them with refined models since the first design step

A sequence variant at 4p16.3 confers susceptibility to urinary bladder cancer

To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldPreviously, we reported germline DNA variants associated with risk of urinary bladder cancer (UBC) in Dutch and Icelandic subjects. Here we expanded the Icelandic sample set and tested the top 20 markers from the combined analysis in several European case-control sample sets, with a total of 4,739 cases and 45,549 controls. The T allele of rs798766 on 4p16.3 was found to associate with UBC (odds ratio = 1.24, P = 9.9 x 10(-12)). rs798766 is located in an intron of TACC3, 70 kb from FGFR3, which often harbors activating somatic mutations in low-grade, noninvasive UBC. Notably, rs798766[T] shows stronger association with low-grade and low-stage UBC than with more aggressive forms of the disease and is associated with higher risk of recurrence in low-grade stage Ta tumors. The frequency of rs798766[T] is higher in Ta tumors that carry an activating mutation in FGFR3 than in Ta tumors with wild-type FGFR3. Our results show a link between germline variants, somatic mutations of FGFR3 and risk of UBC.info:eu-repo/grantAgreement/EC/FP7/21807