Henrik Brøner Jørgensen

Strength of Loop Connections between Precast Bridge Decks Loaded in Combined Tension and Bending

Abstract The paper presents a study of the load-carrying capacity of loop connections subjected to combined tension and bending. For such connections, the main design challenge in practice is to obtain a load- carrying capacity that is governed by yielding of the looped reinforcing bars (i.e., the U-bars) and not by fracture of the joint concrete. Unfortunately, reliable design models serving this purpose have not yet been published. Therefore, in this paper, a design-oriented plasticity model is proposed for the calculation of the N–M interaction diagram accounting for both failure modes. The work is an extension of a model previously developed by the authors for the case of pure tension. In addition to the theoretical work, test results of connections subjected to combined tension and bending are also presented. Calculations according to the model have been compared with tests. Satisfactory agreements have been found.

Bone healing in multiple myeloma: A prospective evaluation of the impact of first-line anti-myeloma treatment.

Myeloma cells disturb a normally balanced bone remodeling process. This imbalance of bone metabolism may cause osteopenic bones, focal osteolytic lesions and clinical symptoms. The excess bone resorption resulting in osteolytic lesions has traditionally been perceived as irreversible. We

Is retention of zoledronic acid onto bone different in multiple myeloma and breast cancer patients with bone metastasis

Zoledronic acid (Zol) is used to treat bone disease in both multiple myeloma (MM) and breast cancer patients with bone metastasis (BC). However, bones of MM and BC patients show a difference in retention of the bisphosphonate used for bone scintigraphy. Therefore, we hypothesized that disease‐specific factors may differently influence Zol retention in MM and BC patients. We tested this hypothesis in an investigator initiated phase II clinical trial in which we compared the whole‐body retention (WBrt) of Zol in a cohort of 30 multiple myeloma (MM) and 30 breast cancer (BC) (20 Zol naive and 40 with six or more previous administrations). On average, 62% of the administered Zol was retained in the skeleton of both MM and BC patients and independently of the number of treatments. WBrt of Zol did not correlate with cross‐linked C‐telopeptide (CTX) levels, but linear regression analyses showed that WBrt of Zol correlated with bone‐specific alkaline phosphatase (bALP) levels in BC (p = 0.001), and with CTX/bALP in Zol naive MM patients (p = 0.012). Especially in BC patients, WBrt correlated with age (p = 0.014) independently of kidney function. In MM patients WBrt was found to primarily correlate with the extent of bone disease (p = 0.028). Multivariate linear regression analyses of the entire cohort pointed out that WBrt of Zol was best predicted by age (p < 0.000), osseous lesions (p < 0.001), and the preceding Zol dosing (p < 0.005) (r2 = 0.97). Comparing bone scintigrams with CT/X‐ray images showed a poor correlation between sites of active bone disease and binding of scintigraphy bisphosphonate in 36% of MM patients and in 13% of BC patients. We conclude that WBrt of Zol is primarily determined by two non‐disease related factors and only one disease related, but that there may be differences in retention or drug delivery at individual sites of bone disease between MM and BC patients. In order to find the optimal dosing of Zol, these observations should be taken into account.

Baseline bone involvement in multiple myeloma - a prospective comparison of conventional X-ray, low-dose computed tomography, and 18flourodeoxyglucose positron emission tomography in previously untreated patients

Examination of bone lesions is a compulsory part of baseline assessments in patients with multiple myeloma (MM). Low-dose computed tomography (CT) scan has recently been recommended as a replacement of conventional X-ray for the diagnosis of osteolytic lesions by the European Myeloma Network.[1][1]

Strengthening Strategy for the Shear Capacity in Existing Concrete Structures

Abstract This paper presents an effective strengthening strategy to increase the shear capacity of existing reinforced concrete structures. The solution is derived by using the upper-bound theorem of the theory of plasticity, a well-known approach in the design of new structures. It is shown how the solution can be effectively used to not only derive the shear capacity, but also to find out where strengthening reinforcements should be placed. The strategy is exemplified by a strengthening project wherein the cross beams on a three-span concrete bridge have insufficient local and global shear capacity. The cross beams are strengthened with unbonded steel bars, which are installed in drilled holes. First, it is shown how the formulation of kinematically admissible failure mechanisms are easily used in the assessment of the capacity of existing structures. Second, it is shown how the solution is effectively used to find the ideal placement of the steel bars. Finally, the paper presents some considerations on the strengthening method. It is argued that it is necessary to prestress the unbonded post-installed steel bars in order to ensure their concurrent contribution with the existing reinforcement and sliding in the concrete.

Influence of High Axial Tension on the Shear Strength of non-shear RC Beams

This paper deals with the influence of high axial tension on the shear strength of beams without shear reinforcement. An experimental program with shear-tension tests was carried out. The experimental results have been used to evaluate the applicability of the Eurocode 2 (EC2) design formula in cases with large normal forces. In addition, the experiments have been used to evaluate an extension of the plasticity based Crack Sliding Model (CSM) to cover cases with large normal forces. The test results show, that even in the present of very high axial tensile stresses and strains, the member is still able to carry significant shear stresses. The analysis reveals that the EC2 formula is over conservative in this regard.