Structural Members Research Articles

Numerical-Computational Model for Dynamic Nonlinear Analysis of Frames With Semi-Rigid Connection Considering the Damping Effect

Objective: the scope of this work is to present a numerical-computational model for transient dynamic nonlinear analysis of frames with geometric nonlinearity and semi-rigid connection. Methodology: the equation of motion, which describes the structural dynamical system, is solved by the a-Generalized direct integration method associated with the standard Newton-Raphson method. The structures are discretized through the co-rotational formulation of the Finite Element Method considering the Euler-Bernoulli beam theory. The semi-rigid connection of structural members (beam-column and beam-support) is simulated by a connection element with zero length, which is described in terms of axial, translational and rotational stiffness. Results and conclusion: From the numerical results of three structural systems (bi-fixed beam, L-shaped frame, and single-story frame) obtained with the free Scilab program, it is concluded that the definition of the type of connection is an important factor to be considered in the analysis of frames subjected to dynamic loads. Furthermore, structural damping, which is a measure of energy dissipation, drives the structure from a vibrating state to a resting state. Research implications: Structural Engineering has been designing systems that cannot be analyzed and dimensioned without dynamic effects being considered. lack of knowledge of the levels and characteristics of the dynamic response can lead to system failure during the application of repetitive loading due to accumulation of structural damage. In this sense, the numerical model can represent a valuable engineering tool when it comes to the dynamic analysis of plane metallic structures with geometric nonlinearity.

Effect of flow characteristics in the inner gate on the microstructure of a semi-solid processed hypereutectic Al–Si alloy

ABSTRACTThis study aims to prepare hypereutectic Al–Si alloy cylindrical samples with hard inner surfaces by changing the depth of inner gates in squeeze casting molds. The characteristic parameters (volume fraction and equivalent diameter) of the hard phases (primary Si and Fe-rich phases) and the hardness of the samples were observed. When the depth of the inner gate is 5 mm, there is a radial gradient in the characteristic parameters of the hard phases in the members resulting in surface strengthening of the structural member. However, when the depth of the inner gate is 9 mm, there is no radial gradient. The mechanisms of achieving surface strengthening in hypereutectic Al–Si alloy cylindrical samples by changing the rheological characteristics of semi-solid Al–Si alloy slurries were revealed.

Analytical and experimental investigation of the flexural and bond adhesive properties of thermally modified rubberwood and hybrid glulam beams with WPVC composites

Thermal modification is a property improvement technique that uses high temperatures to treat wood. For wooden structural members used in construction, in addition to the mechanical properties of thermally modified wood, the wood adhesive bond strength becomes increasingly significant. The present study examined the effects of thermal modification, using various temperatures (180 °C, 190 °C, 210 °C, and 220 °C) on the mechanical properties and adhesive bond performance of rubberwood compared to unmodified rubberwood. The results indicated that increasing the modification temperature negatively affected the mechanical properties of the rubberwood and decreased the wood adhesive bond strength. To improve the durability performance and joint strength reduction, a wood/polyvinyl chloride (WPVC) composite material was combined with thermally modified rubberwood at a temperature of 180 °C, which offered the optimum results in terms of the mechanical properties and wood adhesive bond strength of the various proposed modification temperatures. The study also investigated the mechanical properties of hybrid glulam beams made from thermally modified rubberwood and WPVC composites using static flexural tests, comparing the results to those for the thermally modified rubberwood glulam beams. The findings suggested that the modulus of elasticity of the hybrid glulam beams was not significantly affected because the WPVC composite members were placed in a low load-bearing location. The hybrid glulam beams provided a 38.66 % lower flexural strength than the thermally modified rubberwood glulam beams. Overall, the increase in temperature during the modification process negatively impacted the mechanical properties and wood adhesive bond strength of rubberwood. Moreover, a theoretical analysis was carried out to provide a comparison with the experimental investigation by focusing on the flexural behaviour of glulam beams. The analytical model results showed a good correlation with the observed behaviour of the glulam beams produced by thermal modification at different temperatures. In particular, the behaviour of the glulam beams produced by thermal modification at a temperature of 180 °C could be effectively predicted with high confidence.

Experimental study on flexural and seismic performances of RC members with non-rebar-contact ECC joints

Grout-filled sleeves are widely used to splice steel bars for precast structural members, e.g., beams and columns. However, steel bars are generally densely distributed at the splice and steel bar misalignment always exists in actual practice, which bring huge troubles to building workers when splicing steel bars. To address this issue, the authors used Engineering Cementitious Composites (ECC) as the only material to cast connection region, and expected ECC to take the place of the grout-filled sleeve for connecting longitudinal steel bars. For this purpose, the authors experimentally studied the mechanical behaviors of beams with non-rebar-contact ECC joint by four-point bending tests, and raised a special algorithm to determine the appropriate lap length. Based on the proposed algorithm, three columns with designed non-rebar-contact ECC joints were cast and tested under quasi-static cyclic loads. The test results showed that the specimens exhibited increasing flexural strength, energy dissipation and ductility with the increase of non-contact lap length. When the lap length is sufficiently long, the strength of specimens got close or even higher than that of continuous steel-reinforced specimen, however, the corresponding energy dissipation and ductility are, to some extent, less than those of the continuous steel-reinforced specimen. It is verified that well-designed ECC joint may take the place of grout-filled sleeve for connecting longitudinal steel bars and achieve “continuous steel-reinforcement equivalent” effect.

A novel winding–wedge anchorage for CFRP straps: Conceptual design and performance evaluation

Carbon fibre-reinforced polymer (CFRP) straps can be utilised as tension members in structures on account of their high-strength properties. The development of an effective anchorage device for CFRP straps that can fully utilise the strength of straps before anchorage failure is an ongoing technical challenge. To address such knowledge gap, a novel anchorage device termed winding-wedge anchorage that combines winding and wedge anchorage mechanisms is reported herein. For the winding anchorage component, different numbers of winding turns are applied. For the wedge anchorage component, three different types of wedge anchorage systems are investigated namely bonding, friction clamping, and friction non-clamping. Initially, the working mechanism, theoretical winding–wedge anchorage model (herein theoretical model), and design parameters are determined. Experimental and finite element analyses are then reported to assess the behaviour of the anchorage including failure modes and anchorage efficiencies. The accuracy of the theoretical model is also reported. It is concluded that the efficiency of the anchorage device is primarily dependent on the wedge anchorage component. Moreover, the bonding wedge anchorage component performed better than the other two wedge anchorage systems. The theoretical model and experimental results revealed that 1.5 winding turns results in an optimal interaction between the winding and wedge anchorages components.

Finite Element Analysis and Calculation Method of Concrete-Filled Stainless Steel Tubes under Eccentric Tension

Concrete-filled stainless steel tubes (CFSST) could be used as structural members in corrosion-prone environments. A detailed numerical investigation of the mechanical performance and calculation method of CFSST members under eccentric tension is carried out in this paper. A finite element analysis (FEA) model that adopts three-dimensional elements is established, and related experimental results of CFSST and conventional concrete-filled carbon steel tubes (CFST) subjected to tension are used to validate the FEA model. Then, the calibrated FEA model is used to investigate the performance of CFSST eccentrically tensile members, especially the composite actions and stress distribution laws between the stainless steel tube and the concrete core, which play a key role in the load-carrying capacity of the composite member. To quantitatively determine the influence of different parameters on the load-carrying capacity of CFSST tensile members, a wide-range parametric analysis is performed. Finally, a calculation model is proposed to be used to predict the ultimate tensile strength of CFSST members subjected to eccentric tension, and the model-predicted values show good agreement with the FEA-computed results.

Correction Factor Method As A Substitute For Sequential Construction Analysis Of Buildings

Abstract: Within the sphere of structural analysis, a method of paramount importance emerges - the Correction Factor Method. Unlike conventional approaches, this method stands as a stalwart against the complexities of non-linear structural behavior. It pioneers a path that diverges from the linear norm, offering precision and insight where others falter. The structural parts of the building are analyzed in one step using linear static analysis method by assuming that the structure will be subjected to full load after the finishing of the construction completely. In reality things work in other way the dead load from each structural members and finishing materials are imposed in different stages as the structure is constructed storey by storey. Similarly the stability of frame changes at every stage of construction. Because of this changes the loads assumed in conventional analysis vary in the construction process and the results obtained in the traditional analysis will be unstable. Thus the structural frame should be analyzed in every structural construction stage by keeping variation of loads. This process is called as Construction Stage Analysis this process considers all the uncertainties precisely. This process is a time consuming process as the analysis is a complex process. Thus Correction factor method can be introduced where the analysis time can be reduced and the results will be accurate to Construction Stage Analysis. In this project multistoried reinforced concrete building frames with different number of floors are analyzed using ETABS, and then Construction Stage Analysis of each building model is done. A comparative study of Bending moments, axial forces, twisting moments and shear forces are carried out at every stage of the structural frame. These values are compared with linear static analysis and Construction Stage Analysis. From the values obtained correction factors are derived. From this method we can get results which has a maximum error of 2% and this proves that correction factor can be used as a substitute for sequential construction analysis

A Study on the Characteristics about Shaft Deflection According to the Change in Manufacturing Sequences

Recently, the amount of orders for large container ships based on eco-friendly fuel is increasing. Container ships have very different characteristics of cargo as comparing other type cargo carriers, having a unique arrangement of structural members. In this reason, the classification societies propose major governing conditions that affect independent shaft alignment calculations based on detailed analysis. In this study, the change in displacement around the shaft system, which occurs in the manufacturing process, was investigated using structural analysis modeling. The manufacturing process is divided into PE (Pre-erection), welding according to the erection sequences, lifting the block, setting on the dock, and finally reviewing the launching conditions. The results of this study, the displacement of the shaft system during the manufacturing stages were confirmed. The change in the number of block supports had the greatest effect on the change in deflection rather than the effect of welding heat, and the final results were similar to those of the PE condition. The shaft centering analysis can be predicted correct value in advance if the characteristics of deflection change according to the process are known, and accurate prediction can be made in a short time by using the proposed procedure.

Probabilistic wind uplift resistance framework for the relative evaluation of wood-frame load paths

Past failure risk analyses of wind-impacted wood-frame structural load paths have tended to consider simplified resistance models that account for a few key load path connections, in which connection capacity distributions are generally based on benchmark experimental results. However, recent post-storm reconnaissance studies have demonstrated that connections in the load path of light wood-frame structures are themselves composed of multiple elements with many configurations and possible failure modes. This study presents a flexible approach for modeling wind uplift resistance in wood-frame load paths that includes a more exhaustive set of potential failure points yet is computationally efficient and readily adaptable to various load paths composed of different assemblages of structural members and connections. In this framework, ultimate capacities of connections and wood members are either based on design equations provided in the National Design Specification for Wood Construction or another applicable standard or computed from a comparable mechanics-based model. Analytical capacity estimates for roof sheathing, roof-to-wall connections, and wall-to-slab-foundation connections accord well with the range of published experimental results for these connections. Capacities of connections that act in parallel are summed to transform the load path into an analogous load chain of series components. System-level wind uplift resistance, defined by the weakest component in series, is evaluated by Monte Carlo simulation. By providing a more complete description of resistance than previous simplified models have done while avoiding the expense of a detailed finite-element or other solid mechanics model, the method proposed here holds promise as a rapid, consistent, and accurate way to quantify wind resistance in any arbitrary wood-frame load path, with applications including insurance risk analysis, hybrid data science frameworks utilizing post-storm reconnaissance data, and estimation of hazard intensity from structural damage observations.

Damage prediction of RC columns with various levels of corrosion deteriorations subjected to blast loading

Coastal structures are often exposed to harsh environmental conditions such as saltwater, high humidity, and coastal winds, leading to corrosion damage to the reinforcing steel and degradation of concrete. The blast risk is characterized by a relatively low likelihood but a significant consequence. The blast resistance of structural members with deteriorated properties due to corrosion and the corresponding post-blast performance is of significance to evaluate the lifecycle structural safety facing explosion threats. In this study, the damage of reinforced concrete (RC) columns of coastal structures with various corrosion degrees subjected to blast loading is investigated. The corrosion effect was modelled by considering the deterioration of rebar diameter and yield strength, bond strength between rebar and concrete, and rust expansion pressure effect. The numerical model was validated by simulating drop weight impact tests of RC beams with different corrosion degrees. Based on the validated model, the finite element (FE) models of corroded RC columns with the maximum corrosion degree of 15% were established and their responses and damage to blast loads of various blasting scenarios were calculated. It is found that the blast response of the column increases with the degree of corrosion. The blast damage mode may change from combined shear and flexural damage to concrete spalling damage with the increment of corrosion degree. Furthermore, the residual axial loading capacity and stiffness of post-blast columns were calculated and it is found that they degrade as the corrosion degree increases. A blast damage index is defined in terms of the residual axial loading capacity of the column, which is found to increase with the corrosion degree. The damage amplification factor due to corrosion deterioration (CAF) is then proposed as a function of corrosion degree, TNT equivalent mass, standoff distance, concrete strength, and reinforcement ratio to predict the blast damage of corroded columns.

Use of recycled aggregate concrete in structural members: a review focused on Southeast Asia

ABSTRACT This article presents a comprehensive review on the use of recycled concrete aggregate (RCA) and recycled aggregate concrete (RAC) in construction, with emphasis on structural applications and identification of challenges and opportunities of RCA/RAC materials in Southeast Asia. For the first time and as a first step towards potential standardization of RCA/RAC in Southeast Asia, the article critically examines the physical and mechanical performance of RCA and RAC in structural applications. Global aggregate demand is projected to surpass 50 billion tons by 2025, with major Asian countries accounting for 62% of consumption. At the same time, the global annual production of construction and demolition waste (C&DW) exceeds 3.57 billion tons, and Asia is responsible for 53% of this total. Recycling C&DW plays a crucial role in addressing environmental issues and promoting sustainable construction practices. Previous research indicates that RAC exhibits certain physical and mechanical deficiencies, with strengths 10% to 20% lower than natural aggregate concrete (NAC). At the structural level, RAC elements show reductions of up to 15% in axial, bonding, shear, and flexural strengths relative to NAC. Measures such as treatment of RCA, recycling process optimization, and optimized mixing techniques are recommended to enhance RAC properties. Prioritizing RCA treatment during construction and exploring novel strengthening techniques could elevate improve RAC and make it suitable for structural applications. The review also found that C&DW recycling efforts vary significantly across countries (particularly in Southeast Asia), with some countries lagging regarding recycling technologies and use of best practices. Various strategies to improve the performance of RAC elements are also proposed and discussed. The main findings and shortcomings of previous investigations are critically discussed, and further research needs are identified.

Multivariate Independent Component Analysis Identifies Patients in Newborn Screening Equally to Adjusted Reference Ranges.

Newborn screening (NBS) of inborn errors of metabolism (IEMs) is based on the reference ranges established on a healthy newborn population using quantile statistics of molar concentrations of biomarkers and their ratios. The aim of this paper is to investigate whether multivariate independent component analysis (ICA) is a useful tool for the analysis of NBS data, and also to address the structure of the calculated ICA scores. NBS data were obtained from a routine NBS program performed between 2013 and 2022. ICA was tested on 10,213/150 free-diseased controls and 77/20 patients (9/3 different IEMs) in the discovery/validation phases, respectively. The same model computed during the discovery phase was used in the validation phase to confirm its validity. The plots of ICA scores were constructed, and the results were evaluated based on 5sd levels. Patient samples from 7/3 different diseases were clearly identified as 5sd-outlying from control groups in both phases of the study. Two IEMs containing only one patient each were separated at the 3sd level in the discovery phase. Moreover, in one latent variable, the effect of neonatal birth weight was evident. The results strongly suggest that ICA, together with an interpretation derived from values of the "average member of the score structure", is generally applicable and has the potential to be included in the decision process in the NBS program.

Follow effect of low cost glass fibre reinforced polymer (GFRP) on the performance of concentrically loaded concrete column

(FRP) plays a major role in the strengthening of existing structures due to the age of the structure or natural calamities like earthquakes, floods, cyclones, etc. For reducing the size of structural members, the FRP wrapping assists to achieve the performance of the structure. Concrete is widely used due to its advantages and FRP is added to improve its quality in terms of strength. A study has been conducted on 21 cylinders based on their slenderness ratio. The slenderness ratios in the columns were 8, 16, and 24. At thicknesses of 5 mm and 7 mm, two types of wrap materials (UDCGFRP) and (WRGFRP)] were employed. Up to the point of failure, the columns were subjected to monotonic axial compressive force. The column’s yield loads, and ultimate load, were deduced from the load-deflection curves. The overall, uni-directional cloth provided the most effective confinement and led to a highly desirable failure mechanism, which was a gradual process.

Experimental and statistical investigation on structural feasibility of admixture based foam concrete with hexagonal wire mesh reinforcement

Foam concrete is an emerging construction material with reduced self-weight, high workability and improved thermal resistance. Deployment of this foam concrete for structural applications has not drawn keen attention of the research community. This study reports an investigation on the viability of using admixtures like, crumb rubber, silica fume and polypropylene fiber in foam concrete, reinforced with hexagonal wire mesh for enhanced strength and energy absorption. Taguchi's experiment design methodology was applied for assessment of the optimal mix of foam concrete with admixtures. Mixtures with three factors, namely silica fume, polypropylene fiber (PP fiber), and crumb rubber were developed in an L9 orthogonal array. Compressive and flexural strength parameters were used to establish the best possible mix proportions for maximum strength. Tests were conducted on hexagonal wire mesh (chicken mesh) kept in horizontal, vertical and horizontal with stirrup arrangements and the results were compared with control mix and the selected optimized mix. In all cases, percentage of steel reinforcement for the total volume of the concrete was kept as 1% by adjusting the layers of mesh provided. Based on the experimental results, crack and deflection patterns were analyzed and compared with the control specimen. The test results demonstrated enhanced strength and ductility of the foam concrete, buttressed by hexagonal wire steel mesh, as compared to control specimens. Besides, the reinforcement in the horizontal alignment with admixtures provided better strength and ductility with an enhancement of 130 % in flexural strength and a ductility index of 3.88 compared to control. Prognosis of the study advocated the propriety of using foam concrete as a structural member in construction.

Behavior and design of multi-sided composite sections

ABSTRACT Composite construction is advantageous due to the combination of steel and concrete materials in structural members. Composite column’s cross-section types such as hexagonal, octagonal, and decagonal and high diameter-to-thickness (D/t) ratios are highly desirable in transmission towers, yet not covered in the applicable codes. Therefore, the objective of this study is to investigate the behavior of composite columns with various characteristics including cross-section types, and height and propose a design procedure based on Force – Moment (P-M) Interaction diagrams and related equations. Three-dimensional non-linear finite element models were developed using a nonlinear finite element software to simulate and verify the behavior of the composite towers against prior experimental work. Concrete Damage Plasticity and Steel Bilinear Elasto-Plastic Model were calibrated and used in capturing the realistic nonlinear behavior of the materials and their interaction. Based on the computational models, a concrete reduction factor, needed for the development of design equations, was derived. Conclusively, typical normalized P-M Interaction diagrams were constructed for various polygonal shapes with high D/t ratios beyond code limitations. The corresponding derived design equations play a significant role in the applicability of the composite columns in transmission towers.

Dynamic amplification factor and interactions of a beam under compressive axial force and load travelling at varying velocity

In this article, the deflection profile and response characteristic of axially prestressed continuous beam under the actions of load travelling at non-uniform velocity is explored. To achieve this, The governing equation is transformed using weighted residual method to obtain a set of coupled second-order Ordinary Differential Equations (ODEs) governing the amplitude factors of the beam-mass system. This set of ODEs is further simplified by applying a modified asymptotic method of Struble. Impulse response function is finally employed to obtain solutions representing the responses of this structural member to accelerating masses. Dynamic time history is carried out. Deformation and responses due to the stress in the structure are evaluated for different parameters. Dynamic effects of decelerating, accelerating and uniform velocity-type of motions on the dynamic amplification factor (DAF) and response characteristics are extensively studied for various vital structural parameters such as the beam span length, foundation stiffness, prestress, rotatory inertia correction factor, load position and velocity. The values of the amplification factors (DAF) against various pertinent parameters are presented in plotted curves for the pinned-pinned beam. It is found that, for accelerating, decelerating and constant velocity-type of motion, the value of the dynamic amplification factor increases as the values of axial force, foundation subgrade, and rotatory inertia factor increase. Various useful results in perfect agreement with existing studies are presented. It is further established that variations of the various structural parameters of interest significantly alter the response characteristics of the vibrating system.

Data-driven strategy for geometric imperfection analysis of assembled large-span ring truss components

Assembled large-span ring truss, constructed using circular steel tubes, is gaining popularity as a new structural form. However, the insufficient availability of design and modeling methods for geometric imperfection of components poses a challenge in studying the cumulative effects of these imperfections on the overall structural performance. Therefore, a data-driven strategy for analyzing geometric imperfections in assembled ring truss structural components (circular steel tubes) is presented in this study. The primary objective is to enable the design of geometric imperfections based on measured data and establish a corresponding equivalent calculation model to incorporate the measured imperfections into the structural analysis model. The core of this strategy lies in utilizing the high-precision point cloud data of components obtained through 3D laser scanning technology as the primary input. The geometric imperfection modes are extracted accurately and rapidly by employing a developed algorithm. Furthermore, a comprehensive framework is proposed for establishing the geometric imperfection calculation model based on the identified modes. A case study was conducted to validate the proposed strategy, revealing its high reliability. Moreover, it is recommended to extend this strategy for analyzing geometric imperfections in similar building structural members.

The Structural Behavior of Reinforced Concrete Beams Made with Locally Produced Recycled Aggregate in the UAE

In this study, the feasibility of utilizing locally produced coarse recycled aggregate (RA) from demolition waste in the UAE for structural applications was investigated. A comprehensive literature review on the subject showed that the shear and flexural responses of reinforced beams utilizing aggregate from concrete demolition waste are greatly dependent on the aggregate replacement ratio and the quality of the recycled aggregate. The experimental program in this study consisted of three phases. Phase I focused on the evaluation of the physical and mechanical characteristics of the RA, Phase II addressed the mix design and fresh and hard properties of the concrete, and Phase III dealt with the flexural and shear behavior of structural members. The research involved twelve 150 mm × 300 mm reinforced concrete beams with a length of 1500 mm or 2000 mm that were made with 0% (control), 50%, or 100% recycled coarse aggregate, replacing natural coarse aggregate (NA). Two target concrete compressive strengths, 25 and 35 MPa, were considered in the investigation. The results showed that the recycled aggregates had lower crushing and LA abrasion values by 40% and 18–28%, respectively, whereas the absorption capacity was 40–300% higher compared to the natural aggregate. In addition, the mechanical properties of the concrete made with different replacement ratios (R%) of RA were either similar or slightly less than those of the control mix. The shear beam tests with fc′ = 25 MPa showed that the 50%- and 100%-replacement-ratio beams demonstrated closely matched normalized shear strength values that exceeded their corresponding NA beam by 12.5%, while the shear beam tests with fc′ = 35 MPa showed that the NA beam exhibited normalized shear strength surpassing the 50% RA and 100% RA beams by 12.5% and 17.5%, respectively. In the flexural beam tests, the flexural strength exhibited minimal disparities for the beams that shared the same RA% but differed in their compressive strength targets, and overall, the variation in the RA% had a marginal impact on the flexural strength of the beams. Further, an increase in the RA% corresponded to an increase in the shear ductility index, which was in contrast with the findings on the flexural ductility index. Furthermore, predictions of flexural strength using the ACI318-19 code and shear strength using the strut-and-tie model yielded comparable results to the experimental ones.

Effects of inherent and external factors on the distributions of steel fibers in rectangular section of SFRC

The proposed statistical simulation model (SSM) indicated that greater fiber dosage and smaller diameter tended to increase inherently both mean (μf) and standard deviation (σf) of the distributions of the number of fibers randomly crossing a unit area of SFRC (nf). Furthermore, the SSM indicated that external effects resulting from external vibration and the distribution of SFRC may further increase the values of μf and σf from inherent effects by up to 1.11 and 1.86 times on average, respectively. More specific test guidelines reflecting both effects appear to be necessary along with their interpretation for full-sized structural members.

Evidence of new diapiric structures in the southern Adria Plate (Eastern Margin of Tethyan Ocean): Implications for Triassic paleogeography and evaporites remobilization during subduction/collision (Northern Ionian Sea, Central Mediterranean)

It has long been recognized that the Adria Plate, as well as the Dinaric-Hellenic sector, contains a large volume of Triassic salt associated with diapirism, and it is well known that Triassic evaporites in the Mediterranean Sea region were deposited over epicratonic platforms surrounding the Mesozoic passive margin of Tethys Ocean. However, the real extent of these evaporites is still unknown; especially in the deep-water offshore area where publicly available seismic reflection profiles are scarce and petroleum exploration wells are missing. Several authors highlighted the presence of Triassic salt structures, mostly triggered by Meso-Cenozoic compressions and associated with fold-and-thrust belts. Both the lack of data and the later compressions contribute to hiding how a diapiric structure, formed in a passive margin and characterized by dome's geometry, is remoulded to assume a teardrop geometry typical of diapirs in fold-and-thrust belts. Two end members of diapiric structures are discussed: extensional structures formed in a passive margin, and compressional structures formed in a fold-thrust belt. The transformation of one end-member into the other is not well known. In the Northern Ionian Sea, the Apulian foreland, belonging to the southernmost termination of the Adria Plate and considered one of the largest preserved Mesozoic passive margin block of the Tethys Ocean, is a deep-water area associated with the opposing fronts of the nearby Calabrian Arc/Apennines and Dinaric-Hellenic Chains since the Cretaceous. Therefore, it represents an ideal area for investigating both the real extent of Triassic evaporites and the transformation of the diapiric structures under different regional geodynamic contexts.Based on seismic reflection profiles but no petroleum exploration wells, we present evidence of Triassic evaporites in the deep-water portion of the Apulian foreland, as indicated by the interpretation of two diapiric structures never described previously. These two new diapirs likely formed from inherited Mesozoic salt structures such as pillows and/or salt domes. The identification of halokinetic-related sequences affecting the Plio-Quaternary foreland sediments allows constraining the polyphaser evolution of the two diapirs. We suggest they are reactivated in response to the compressive stresses transmitted by the nearby Calabrian Arc/Southern Apennines and Hellenides. But, after the Middle Pleistocene, extensional tectonics, related to Adria Plate flexuring, acted again, and the diapirs were cross-cut by normal faults. These observations and findings are integrated into the geological context that controls the fundamental features of the diapirs, providing new insights on the fate of diapiric structures formed in a passive margin, later involved in a subducting and colliding plate, and before they become part of a fold-and-thrust belt. Furthermore, the study provides new constraints on the Triassic paleogeographic reconstruction of the Northern Ionian and Central Mediterranean Seas at the continental margin of the Tethys Ocean.