Trenutni srpski propisi za proračun - prelazak sa determinističkog na polu-probabilistički pristup

The Serbian design code for reinforced concrete structures is somewhat out-of-date in its approach to structural design. In this paper, a study into the possible transition to a semi-probabilistic approach is presented. Firstly, the implicit reliability indices in the current Serbian reinforced concrete design code are determined for three design situations - bending, axial compression and shear and for various cases within each of them. The implicit reliability indices show that the Serbian design code is more conservative than Eurocode 2, but that design for shear without stirrups has a significantly low reliability index (2.27). Secondly, a calibration procedure was implemented in order to obtain partial safety factors for a target reliability index of 4.8 (calculated as the average of the implicit reliability indices). The obtained partial safety factors are ready-for-use with the current Serbian design code and, as expected, are higher than those in Eurocode 2.Srpski propis za proračun armiranobetonskih konstrukcija je relativno zastareo u svom pristupu. U ovom radu sprovedena je analiza mogućnosti prelaska na polu-probabilistički pristup definišući i parcijalne faktore sigurnosti i na strani nosivosti. Prvo su određeni indeksi sigurnosti, implicitno sadržani u važećem propisu, za tri proračunske situacije - savijanje, centrični pritisak i smicanje i za nekoliko slučajeva u okviru svake situacije. Izračunati indeksi sigurnosti pokazuju da je važeći srpski propis konzervativniji od Evrokoda 2 osim proračunski slučaj smicanja bez armature koji ima izuzetno nizak indeks sigurnosti (2.27). U drugom delu je primenjen postupak kalibracije radi dobijanja parcijalnih koeficijenata sigurnosti za ciljani indeks sigurnosti od 4.8 (dobijen kao srednja vrednost implicitnih indeksa sigurnosti). Rezultujući parcijalni koeficijenti sigurnosti su, očekivano, veći nego oni u Evrokodu 2, a moguća je njihova direktna upotreba uz važeći srpski propis

Procena indirektnih troškova usled prekida putne veze zbog smanjenja funkcionalnih performansi mosta

Stability and bearing capacity of the most important engineering structures of road sections (bridges, tunnels, viaducts, etc...) have enormous influence on the functional performance of the entire highway network. The bridges over torrential rivers are the most vulnerable, which unfortunately has been manifested in May floods in 2014 on the large part of the Serbian national highway network. Structural damage on bridges, inflicted in floods, reduce bearing capacity and designed traffic flow performance of bridges, as well as their capacity to provide safe traffic for all road users. In addition to the direct costs related to the reconstruction of the bridge structure, a partial restriction or in the worst case total traffic suspension due to bridge collapse, leads to a significant increase of indirect costs of road users. In fact, topic of this paper is efficient assessment of the indirect costs due to partial or complete closure of highway section due to damage on bridge structural elements. The VISUM simulation model of one part of the Serbian national highway network was used as a basis for the vulnerability assessment of links that cross over the bridges endangered by floods.Stabilnost i nosivost najvažnijih inženjerskih objekata na deonicama puta (mostovi, tuneli, vijadukti, itd.) imaju ogroman uticaj na funkcionalne performanse cele putne mreže. Najviše su ugroženi mostovi preko bujičnih reka, što je na žalost i potvrđeno tokom majskih poplava 2014. na većem delu putne mreže Srbije. Oštećenja na konstrukciji mosta, nastala u poplavama, smanjuju nosivost i projektovani kapacitet mostova, kao i njihovu sposobnost da obezbede siguran saobraćaj za sve korisnike putne deonice na kojoj se oni nalaze. Delimična obustava ili u najgorem slučaju potpuni prekid saobraćaja usled rušenja mosta, pored direktnih troškova vezanih za obnovu mostovske konstrukcije, dovode do značajnog rasta indirektnih troškova korisnika puta. Tema ovog rada je upravo efikasna procena indirektnih troškova usled delimičnog ili potpunog zatvaranja deonice puta zbog oštećenja na konstrukciji mosta. Simulacioni model u VISUM-u jednog dela nacionalne mreže Srbije korišćen je kao osnova za procenu ‘‘ranjivosti’’ linkova koji prelaze preko mostova ugroženih poplavama

Prikaz vanrednog prevoza na putnoj mreži Republike Srbije

U radu je dat prikaz vanrednog prevoza na putnoj mreži Republike Srbije. Razmatrane su dozvole za vanredni prevoz koje izdaje javno preduzeće Putevi Srbije za dva reprezentativna meseca april i septembar u 2019. godini. Analizirani su sledeći podaci: dimenzije vozila, broj osovina, ukupna masa vozila, kao i preopterećenje po osovinama. U prvom delu rada prikazan je kratak pregled dosadašnje analize vanrednog prevoza u Evropi i svetu tokom prethodnih 20 godina. kao i tendencije i očekivanja u narednom periodu. Drugi deo rada predstavlja statističku obradu i analizu podataka iz razmatranih dozvola za vanredni prevoz na teritoriji Republike Srbije. Na kraju su dati diskusija i zaključci na osnovu urađene analize podataka iz dozvola

New technical solution of the bridge database in the Republic of Serbia

Ради ефикасног одржавања мостова, у свету су развијени системи одржавања мостова(Bridge management system –BMS). У циљу унапређења и даљег развоја, ЈП Путеви Србије су иницирали пројекат под називом: Ажурирање методологије за преглед и вредновање стања мостова и израда нових апликација за управљање базом података о мостовима. У раду је приказано ново техничко решење базе података о мостовима, на основу кога је успостављена и нова апликација.or efficient bridge maintenance, bridge management systems (BMS) have been developed worldwide. In order to improve and further develop, PE Roads of Serbia has initiated a project entitled: Updating the methodology for reviewing and evaluating the condition of bridges and developing new applications for managing the database of bridges. The paper presents a new technical solution for the database on bridges, based on whicha new application was establishe

А practical method for strut-and-tie modelling of the bridge pile cap

Pile cap is a typical example of a discontinuity region, where the classical beam theory does not apply. Therefore, strut-and-tie (STM) model is considered appropriate for the analysis of pile caps. Although, the strut-and-tie method is a powerful tool, one of its shortcomings is the need for guidelines for the standardized models. Otherwise, it is left to the designer to come up subjectively with the STM model, which is a sensitive task. In literature, usually simple loading (axial compression or compression with bending only in one direction) on a four-pile cap is discussed. In practice, for real bridge structure, usual loading is alternate biaxial bending, along with compression, on much larger number of piles, making the typical four-pile caps models useless. A practical methodology for creating pile cap model with large number of piles and with complex loading is presented step-by-step. It is further illustrated for the cases with six piles and eight piles from the actual bridge structures, where the method was applied in practice

Aspekti zaštite životne sredine u okviru baza podataka o mostovima u Republici Srbiji

U republici Srbiji postoji Baza podataka o mostovima još od devedesetih godina prethodnog veka. Ova baza je u nadležnosti JP Putevi Srbije pod čijom inicijativom je izvršena revizija podataka iz baze i, u okviru projekta: Ažuriranje metodologije za pregled i vrednovanje stanja mostova i izrada novih aplikacija za upravljanje bazom podataka o mostovima, izrađena je nova metodologiji na kojoj je zasnova tekuća verzija ove baze. U radu je opisano novo tehničko rešenje baze podataka o mostovima koje je primenjeno kroz novu Software-sku aplikaciju Baze podataka o mostovima. Prvobitna verzija baze je sadržala segmente, koji, na žalost, nisu aktivirani a odnose se na preduzete mere održavanja i odgovarajuće troškove. Predviđeno je da se ovi segmenti popunjavaju sukcesivno u narednom periodu. Kako u vreme nastanka baze (rane devedesete godine prošlog veka) aspekt zaštite životne sredine nije bio u dovoljnoj meri zastupljen, kako u okviru projektovanja, izgradnje ili tokom eksploatacije objekata, postojeća baza nije tretirala ova pitanja. Tokom daljeg razvoja baze predviđa se da se i ova problematika uzme u obzir

Risk management in civil engineering

Risk is involved in the whole lifecycle of a structure: design, construction, utilization and demolition. There is a close connection between reliability and risk. Contemporary building codes introduce consideration of the reliability in structural design. Here, the concept of risk takes into account the level of consequences of a failure. Structural engineers, used to deterministic calculation procedures, are often unfamiliar with the uncertainties associated with risk analysis. An overview of the basic principles of risk management in civil engineering is presented in this paper

Methodology for the formation and development of the database of retaining structures

One of the key problems that occurs in the management of the maintenance of state transport infrastructure facilities is the lack of systematized and updated information on the condition of the elements of infrastructure facilities such as the condition of embankments, bridges, tunnels, retaining structures etc. Systematized information enables rational, efficient maintenance, timely reactions that will reduce the risk of building failures and increase traffic safety. In addition, such an approach contributes to the optimization of the allocation of budget funds for that purpose and the rational use of available technical resources. Management of the maintenance process of retaining structures requires the formation of a unique (central) database that will record all retaining structures that meet the prescribed criteria for recording and systematically monitor their condition over time. This paper presents the methodology for the formation and development of a database of retaining structures, using examples of good practice.Српско друштво за путеве “Via Vita

Quality control plans for road bridges

The road authorities are bound to provide desired quality of service (QoS) to road users, or in more concrete terms fast, safe, comfortable and affordable travel. To this end, timely maintenance interventions are sometimes required and the purpose of the quality control plans is to specify circumstances under which the interventions should be triggered in order to ensure the desired QoS. The brief overview of the documents pertinent to bridge quality control revealed a large disparity in Europe with regard to the required QoS and its evaluation. The aim of the COST Action 1406 is to bring together, both researchers and practitioners in order to accelerate the establishment of a European guideline on this subject. In this paper the conceptual framework is presented that will guide the effort of the Action’s Working Group 3 “Establishment of a QC plan” to provide a consistent set of triggering criteria for maintenance interventions