Search results for "Lever"
showing 10 items of 191 documents
Mediating International Conflicts: The European Union as an Effective Peacemaker?
2015
This article examines how the EU's effectiveness as a mediator in peace negotiations can be appropriately conceptualized and analysed. Mediator effectiveness is analysed along two dimensions: goal-attainment and conflict settlement. Investigation of the conditions of mediator effectiveness is structured around four key sets of variables: mediator leverage, mediation strategy, coherence and the conflict's context. In our empirical analysis of EU mediation between Serbia and Kosovo (Belgrade–Pristina dialogue) we find that the medium degree of EU effectiveness (both in terms of goal-attainment and conflict settlement) can be explained by its great leverage vis-a-vis the conflict parties due t…
Conceptual design of prestressed slab bridges through one-way flexural load balancing
2013
In this paper a study on prestressed concrete slab bridges is presented. A design philosophy based on the concept of load balancing through prestressing is proposed in order to minimize the effects of delayed deformations due to creep. Aspects related to the stress redistribution inside these bridges for time-dependent phenomena are analyzed and discussed, by applying the principles of aging linear visco-elasticity. Prestressing is seen as an equivalent external load which counterbalances the permanent loads applied to the bridge, nullifying the elastic deflections due to sustained loads, and thus avoiding the related delayed deformations. An optimization of the structural behavior through …
Serviceability and Ultimate Safety Checks of SegmentalConcrete Bridges through N-M and M-V Interaction Domains
2015
In current engineering practice, safety checks on serviceability and determinations of ultimate limit states of segmental bridges built by cantilevering are generally performed, either considering separately the contributions of axial force N, bending moment M, and shear force V, or considering the interaction effects through approximate expressions supplied by building codes. During construction stages and service life, the interaction between internal forces can be of fundamental importance in establishing the actual degree of structural safety and, for this reason, a different philosophy for performing checks in segmental bridges is proposed in this paper, plotting N-M and M-V interactio…
Simplified model for compressive response of RC column footing with square cross-section
2017
Abstract In this paper, a simplified calculus model for the prediction of the compressive response of RC column footing with a square cross-section is presented. As it is well-known RC concrete footing are designed adopting uniform contact pressures on the substrate and assuming a strut and tie model in deep members and a cantilever beam or slab model in flexible members. Deep and flexible members are distinguished in literature only based on the tangent of the angle expressed as the ratio between the depth and the shear span of the footing. In this paper, several subgrade contact pressures distribution for column footings (rigid or soft soils) were considered in developing a mechanical mod…
Partial Elastic Scheme Method in Cantilever Construction of Concrete Arch Bridges
2013
AbstractIn this paper, a study about stay stressing procedures of concrete arch bridges built by cantilevering with temporary stays is presented. Particularly, the partial elastic scheme method is proposed to find the initial cable forces, and a forward procedure is implemented to follow the actual sequence of construction by extending a procedure already applied to concrete cable–stayed bridges. The theoretical treatment is followed by a numerical application on a case study of a concrete arch bridge, and a comparison between initial cable forces found by the partial elastic scheme method and classical backward analysis is presented here. Results show the effectiveness of the proposed proc…
The influence of time-dependent phenomena in segmental construction of concrete cable-stayed bridges
2011
Construction stages of a cable-stayed bridge are characterized by a sequence in which geometric configuration, restraints and consequently stress and strain patterns vary many times till the final arrangement is achieved. When construction of concrete bridges is made by cantilever method the influence of time-dependent phenomena becomes significant. In this study an evaluation of stay stressing procedures is given by taking into account creep and shrinkage in cantilever construction of concrete cable-stayed bridges. A methodology of stay stressing is proposed with the final target of reaching the desired geometric configuration. Comparison with classical analyses performed by backward metho…
A parametric study of curved incrementally launched bridges
2013
Abstract The structural behaviour of incrementally launched bridges in the construction stages depends on different parameters involving deck, nose, supports and guide devices, because static schemes vary continuously with the advance of the deck above the piers. For this reason temporary stresses in the deck, during launching, are rather different from those occurring in service life. Horizontally curved launched bridges also present the effects of torsion induced by geometric curvature. A parametric study is presented in order to analyse the influence of design parameters on the construction of these bridges. Analyses were carried out by extending to curved beams a procedure based on the …
Serviceability of segmental concrete arch-frame bridges built by cantilevering
2013
The evaluation of the safety degree in service life for a segmental prestressed concrete bridge built by the cantilever method presents different aspects related to strength, deformability, durability and to effects of time-dependent phenomena as creep and shrinkage. The case-study of a prestressed concrete frame bridge with inclined piers is presented, built by cantilevering, with precast segments. By considering the fundamental items of design and construction stages, the implications due to the arch effect in this static scheme are investigated, with respect to an equivalent bridge with a final scheme of continuous girder on vertical piers. The birth of a significant value of axial force…
Can business model innovation help SMEs in the food and beverage industry to respond to crises? Findings from a Swiss brewery during COVID-19
2021
PurposeThe purpose of this paper is to show how different business model innovations (BMIs) help small and medium-sized enterprises (SMEs) in the food and beverage industry to navigate turbulent and uncertain environments such as the coronavirus economic crisis (COVID-19).Design/methodology/approachThe paper adopts an in-depth case study approach and uses a dynamic business modeling (DBM) approach to analyze how a pioneer craft brewery in Switzerland implemented innovative actions undertaken during the COVID-19 pandemic.FindingsThe paper offers a novel framework describing three processes helping SMEs to implement innovations in their business model (BM) to respond in an effective way to cr…
The relationship between entrepreneurship, innovation and growth in Italy
2019
This chapter considers innovation driven by academic entrepreneurship a strategic lever that can accelerate the development of weaker local economies especially in Southern Italy. The analysis of this form of entrepreneurship follows multidimensional approach of the “strategic entrepreneurship” to capture possible correlations between the single analysis approaches widespread in the literature (teleological, psychological, environmental and relational). The chapter intends to launch a reflection on the role of the University inside two particular innovation ecosystems, science and technology parks and research spin-offs. In this way the study of the entrepreneurial phenomenon will explore t…